H+Line Practical Guide for Group 2 Medical Locations

H+

Lin

e P

ractical guide for group

2 med

ical locations H+LinePractical guide for group 2 medical locations

2CS

C47

0010

B02

02 -

08/

2012

- 1

.000

Pz.

Contacts

ABB SACEA division of ABB S.p.A.Modular DevicesViale dell’Industria, 1820010 Vittuone (MI) - ItalyTel.: +39 02 9034 1Fax: +39 02 9034 7609

www.abb.com

Data and images are not binding. Depending on technical development and the products, we reserve the right to modify the content of this document without notice.

Copyright 2012 ABB. All right reserved.

Practical guide for group 2 medical locations 1

Practical guide for group 2 medical locations

contents

1 Introduction

1.1 Premise and purpose of the document ......................... 21.2 ABB serving efficiency in the hospital structures .......... 31.3 ABB‘s references in the hospital sector ........................ 4

2 Why it is important to design and implement a system according to the standards

2.1 Definitions and nomenclature ....................................... 6 2.1.1 Medical locations .......................................................... 6 2.1.2 Medical electrical equipment ........................................ 7 2.1.3 Medical electrical systems ............................................ 8 2.1.4 Applied part .................................................................. 8 2.1.5 Extraneous conductive part ....................................... 10 2.1.6 Group 0, 1 and 2 medical locations ........................... 10 2.1.7 Patient environment .................................................... 14 2.1.8 Medical IT System ....................................................... 15 2.1.9 Main distribution board ............................................... 16

3 Implementation of systems in medical locations

3.1 Area of application of the standard ............................ 183.2 Safety prescriptions for medical locations ................. 18 3.2.1 Equipotential bonding ................................................. 21 3.2.2 Medical IT System ....................................................... 27 3.2.3 Insulation monitoring devices ..................................... 31 3.2.4 Insulation monitoring devices for 230 V lines ............ 33 3.2.5 Insulation monitoring devices for 24 V lines .............. 38 3.2.6 QSD remote signalling panels .................................... 403.3 Implementation of the electrical system ..................... 43 3.3.1 Electrical switchboards ............................................... 43 3.3.2 SMISSLINE - Pluggable System ................................ 47 3.3.3 Ducts ........................................................................... 49 3.3.4 Power supply ducts for radiological or similar equipment ................................................... 50 3.3.5 Selectivity of the protection devices .......................... 50 3.3.6 Installation criteria ....................................................... 51 3.3.7 Earthing ....................................................................... 52 3.3.8 Safety services ............................................................ 52 3.3.9 Safety lighting ............................................................. 53

4 Other information on systems for medical locations

4.1 Veterinary premises .................................................... 54 4.1.1 Electrical risk ............................................................... 54 4.1.2 Criteria for sizing and protecting the electrical system ................................................... 55 4.1.3 The Medical IT System in veterinary premises ........... 55 4.1.4 Inspections in veterinary premises ............................. 554.2 Initial and periodic inspections ................................... 56 4.2.1 Initial inspections ........................................................ 56 4.2.2 Periodic inspections ................................................... 61 4.2.3 Recording of the results ............................................. 61

5 Appendix

5.1 Logical path for the design of electrical systems in premises for medical use ........................................ 625.2 Options for design ...................................................... 635.3 Electromedical devices with applied parts ................. 665.4 Laws and decrees ...................................................... 66

2 Practical guide for group 2 medical locations

1Introduction

This document is the result of the many years of experience of ABB in the hospital sector and the day-to-day relationship with our customers who operate in this sector, which has made it possible to explore real world issues and applications in depth, while continuously comparing regulatory aspects with technical/installation aspects.We would like to thank all the ABB customers who shared their everyday experience with us for the great sensitivity shown in protecting the safety of the patients.

1.1

Premise and purpose of the documentThe aim of this document is to illustrate the guidelines provided by IEC 60364-7-710, which are required for the implementation of the electrical systems inside group 2 medical locations: these types of environments involve high risks for patients and, consequently, require the implementation of additional measures compared to traditional domestic and residential electrical systems.

The document is also intended as an aid to anyone approaching this type of system for the first time, which involves specific design criteria and responsibilities for designers and installers.


1

INT

RO

DU

CT

ION

1.2

ABB serving efficiency in the hospital structuresImplementing a hospital environment involves knowing how to choose and install products with appropriate characteristics. ABB offers a complete range of products in this area for preparing each individual environment, from operating theatres to service rooms, in order to guarantee the best possible organisational conditions in hospitals, clinics, retirement homes, dental or veterinary clinics that will enable healthcare staff to carry out their duties efficiently and to offer patients continuous and high quality assistance in a completely safe environment.

For example, communication between patients and medical-nursing personnel is guaranteed by the modern Clinos 3000 system, with different versions for only acoustic-luminous calls or also equipped with the possibility for direct voice communication between the individual patients and the staff. QSO switchboards are available for the electrical equipping of operating theatres. Thanks to insulating transformers and ISOLTESTER and SELVTESTER devices, it is possible to protect the system from indirect contacts, without automatically breaking the circuit at the first fault.

ABB also provides all the products and systems necessary for the implementation of the electrical systems and automation of the various technological systems in the building: from general electrical switchboards to circuit breakers for controlling lights, from building-automation systems with EIB/KNX systems to high energetic efficiency drive units and motors for air conditioning and hydrothermal systems, from open and moulded-case circuit breakers to the wall-mounted and flush-mounted consumer units, from plastic and metal ducts to floor foundation systems. The protection, command, control and measurement functions can be implemented, not only by means of general-use devices for electrical distribution, but also using specific devices, such as RCD blocks, RCDs, surge arresters and a huge range of DIN bar products.

All ABB products are designed and manufactured to operate in a perfectly integrated manner, allowing the implementation of the best solutions for optimising investments and maximizing results in terms of quality, cost control and operational efficiency

In all situations, and to meet all requirements, choosing ABB products means entrusting the operation and management of your systems to a leader company in the energy and automation sectors, which has always been in the forefront of the manufacture and supply of components and systems for hospital applications.

> Communication between medical and nursing staff

> Products designed for integration


1

INT

RO

DU

CT

ION

The Hospital “Circolo e Fondazione Macchi” - Varese

The Hospital “Circolo e Fondazione Macchi” - Varese

1.3

ABB’s references in the hospital sectorThe experience of ABB in the hospital field is based on and certified by a series of implementations that represent the best from a technological perspective.The following is a list of the most important hospital structures with which ABB has collaborated recently:• The Humanitas Clinic in Rozzano, Milan• The Columbus treatment clinic - Milan• The Gaetano Pini Orthopaedic Institute - Milan• The Niguarda Ca’Granda hospitals - Milan• Spedali Civili in Brescia• The “Città di Brescia” hospital, Brescia• The Fondazione Poliambulanza in Brescia• The Ospedale di Circolo and Fondazione Macchi - Varese• The Aosta regional hospital• The Hospital Centre of Castelfranco Veneto, Treviso• The Hospital Centre of Montebelluna, Treviso


1

INT

RO

DU

CT

ION

The Hospital Centre of Castelfranco Veneto (TV)

The Niguarda Ca‘Granda hospitals - Milano

Spedali Civili in Brescia

Spedali Civili in Brescia

6 Practical guide for group 2 hospital environments

2.1

2Why it is important to design and implement a system according to the standards

IEC 60364-7-710 <Art. 710.2.1

Definitions and nomenclatureBefore examining the ways in which systems for medical location are implemented, we provide a number of definitions that will make it easier to understand the remaining sections of this document.

2.1.1

Medical location

location intended for purposes of diagnosis, treatment (including cosmetic treatment), monitoring and care of patients

Medical locations may also consist of a group of rooms, so long as they are connected functionally, even if not directly communicating, and intended for diagnostic, therapeutic, surgical, patient monitoring or rehabilitation purposes (including aesthetic treatments) The operating room, pre-anaesthesia room, and waking-up room are, for example, functionally connected rooms. Medical locations are environments with a greater electrical risk than ordinary premises because patients may find themselves in conditions of increased vulnerability and subject to the application of electromedical devices.Therefore, particular techniques must be adopted for electrical systems in order to guarantee maximum safety for patients.

Type of premises Examples Max touch voltage (UL) allowed

Medical locations outpatients department

25 V

ordinary rooms waiting room 50 V


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

Medical locations

Increased electrical risk

Greater protection of safety

Group 2 rooms

Figure 2.1: Medical location (above) and ordinary room (down)

2.1.1 continued

Medical electrical equipment

Electrical equipment, provided with not more than one connection to a particular supply mains and intended to diagnose, treat or monitor the patient under medical supervision and which makes physical or electrical contact with the patient, and/or transfers energy to or from the patient, and/or detects such energy transfer to or from the patient. The equipment includes those accessories defined by the manufacturer as being necessary to enable normal use of the equipment.

The power supply can also be obtained by means of an internal electrical source.Medical electrical equipment can be categorised as class I or class II depending on their degree of insulation. In class I devices, protection against indirect contact is guaranteed by connection to a safety conductor (Fig. 2.2.a), while class II protection is intrinsic in that it is provided by double insulation or reinforced insulation (Fig. 2.2.b).

a

b

Figure 2.2: Medical electrical equipment

2.1.2

> IEC 60364-7-710 Art. 710.2.3


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.3

2.1.4

Medical electrical system

Combination of items of equipment, at least one of which is an item of medical electrical equipment and inter-connected by functional connection or use of a multiple portable socketoutlet. The system includes those accessories which are needed for operating the system and are specified by the manufacturer.

Medical electrical systems are groups of multiple electromedical devices or of electromedical devices with other non-electromedical devices, connected electrically both for the transfer of data or signals, and through their power supply. One example could be a device that monitors the physiological parameters of a patient and transfers the corresponding data to another piece of equipment which in turn processes them in order to provide information useful for diagnosis.

Figure 2.3: Medical electrical system

Applied part

A part of the medical electrical equipment which in normal use- necessarily comes into physical contact with the patient for the equipment to perform its function, or- can be brought into contact with the patient, or- needs to be touched by the patient

The applied part can be an electrode external or internal to the body or a surface of the device that, for functional reasons, must be brought into contact with the patient.As regards the type of applied part, medical electrical equipment are divided into devices with parts applied of type CF, BF and B, classified in order of decreasing safety.

Part applied

Symbol Description

CFDevices whose applied part is earth insulated (F = floating) and can be placed in direct contact with the heart since their applied part is insulated

BF

Devices whose applied part is earth insulated (F = floating), but which provide a lesser degree of protection than CF devices. They are therefore not suitable for direct cardiac application

BDevices whose applied part is not earth insulated. They are therefore less safe as regards earth leakage

IEC 60364-7-710 <Art. 710.2.1


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

Figure 2.4: Example of an medical electrical equipment with applied part

Figure 2.5: Example of an medical electrical equipment without applied part

2.1.4 continued


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.5

Extraneous conductive part

A conductive part that is not part of the electrical system, which can introduce a potential, generally the earth potential.

Examples of extraneous conductive parts include metal ducts for gas, water, for heating and for medical gases, the operating table, air conditioning ducts and the metal elements of the building, such as metal window frames that extend outside the premises or the structures supporting the plasterboard of the walls. The metal elements present in the premises are to be considered as extraneous conductive parts if they present resistance to earth:R < 0,5 M in group 2 medical locations where a microshock hazard exists (for example, surgery rooms in general)R < 200 in group 1 and group 2 medical locations where there is not, however,

any hazard of microshock, but only of macroshockR < 1.000 in ordinary rooms

2.1.6

Group 0, 1 and 2 medical locationsThe IEC 60346-7 classifies medical locations use as follows:

group 0 rooms: medical location where no applied parts are intended to be used.

These include outpatients departments and massage rooms where electromedical devices are not used;

IEC 60364-7-710 <Art. 23.3

IEC 60364-7-710 <Art. 710.2.5

Figure 2.6: Group 0 medical locations, outpatients department

1 Conductive parts2 Extraneous

conductive parts3 Extraneous

conductive part (if the table is not electric)


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.6 continued

group 1 rooms: medical location where applied parts are intended to be used externally or invasively to any part of the body, except for the cardiac zone.

These are rooms where electromedical devices with parts applied externally or also internally to the patient's body - except for the cardiac zone - are used;

group 2 rooms: medical location where applied parts are intended to be used in applications such as intracardiac procedures, operating theatres and vital treatment where discontinuity (failure) of the supply can cause danger to life

These are premises where electromedical devices with catheters, with conductive fluids or electrodes are applied in the cardiac zone or directly to the patient's heart, with a consequent microshock hazard. Group 2 rooms also include those in which patients undergo vital treatments, such that the lack of power supply may involve a risk to life, as well as operation preparation rooms, surgical plaster rooms or post-operative waking-up rooms for patients who have undergone general anaesthesia.

Figure 2.8: Group 2 medical locations, operating room

Figure 2.7: Group 1 medical locations, hospital accommodation room

> IEC 60364-7-710 Art. 710.2.6

> IEC 60364-7-710 Art. 710.2.7


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.6 continued

Ordinary roomsThese are service rooms for the medical structure, such as offices, rooms for personnel (for example, changing rooms, canteen, etc.), store rooms, corridors for access to accommodation rooms, service rooms, staff hygiene facilities, waiting rooms etc.

Is it a room intended for medical use, in other words, intended for diagnostic, therapeutic, surgical, patient monitoring or rehabilitation (including aesthetic treatments)?

YES

NO Other type of rooms:for example ordinary

Is at least one medical electrical equipment with applied parts used?

YES

Group 0NO

Are intracardiac interventions or other surgical operations with hazard of microshock performed?

or

is the patient subjected to vital treatments where a lack of electrical power could put the patient's life in danger?

or

Are operation preparation, surgical plaster, post-operative waking-up activities carried out and is general anaesthesia practiced?

Group 1NO

Group 2YES

The classification of the rooms, which must be carried out according to the normal use of the environment, and the identification of the patient environment must be performed by medical personnel or in agreement with the healthcare organization, which must indicate which medical treatments are to be carried out in the room in question.In order to identify the group to which the room belongs, risks of macroshock and microshock and situations of general or local anaesthesia must be taken into account .

P NMacroshock is identified <with electrocution, in

other words the circulation of current through the body that

occurs when two portions of skin are subjected to a

difference of potential (for example between hand

and hand or between one foot and the other).

In this case the current is divided over several paths

and only one part may involve the thoracic

region and touch the cardiac muscle, and

therefore it can be hazardous for persons in a normal state of health

when it reaches intensities close

to 40 ÷ 60 mA

Figure 2.9: Flow diagram for identifying the type of room


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

> Microshock occurs when a difference of potential, which may even be very small, is applied directly to the cardiac muscle through an intracardiac sensor or a catheter (but also a surgical knife that is a good conductor which is accidentally live). In this case, all the current excites the cardiac mass with greater intensity at the point of application of the probe, causing a high probability of triggering fibrillation. The current becomes hazardous if it exceeds 10 ÷ 60 microampere, values that are several thousand times lower than those of the macroshock

2.1.6 continued

IB

P N

Examples of classification of medical locations

Type of room Group 0 Group 1 Group 2

Massage room

Hospital accommodation rooms

Delivery room

ECG, EEG, EHG, EMG room

Endoscopy room (1)

Outpatient departments (1)

Urology room (1)

Radiology and radiotherapy diagnostic rooms

Hydrotherapy room

Physiotherapy room

Anaesthesia room

Room for surgery

Operation preparation room (2)

Surgical plaster room (2)

Post-operative waking room (3)

Room for applications of cardiac catheters

Intensive care room

Angiographic and haemodynamic analysis room

Haemodialysis room

Magnetic resonance room (MRI)

Nuclear medicine room

Premature infant room

(1) If not a surgical operating theatre.(2) If general anaesthesia is practiced.(3) If it holds patients while they are waking up from general anaesthesia.


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

Patient environment

Any volume in which intentional or unintentional contact can occur between patient and parts of the system or between patient and other persons touching parts of the system.

The centre of reference in order to determine the patient environment may be, for example, the operating table, the bed in the hospital accommodation room or the dentist's chair.The patient environment does not extend more than 2.5 m above the walking surface and outside the premises. Note that the patient environment can be the container of the patient environments relating to the positions in which the patient may reasonably be located while in contact with applied parts. Similarly, if there are multiple and/or movable electromedical devices, the patient environment is extended to include at most the entire premises. Therefore account is taken of possible movements to which the electromedical devices or the patient may be subjected over time.Determining the patient environment during the design phase makes it possible to avoid connection of the extraneous conductive parts located outside the patient environment to the equipotential node, reducing the size of the node and simplifying installation, with a consequent reduction of costs. This means therefore that all the possible positions in which the patient may be located while in contact with an electromedical device with applied parts must be established in advance; otherwise, there is a risk that the electrical system will be inadequate when, for medical needs, it becomes necessary to move an medical electrical equipment with parts applied into a position other than those positions originally envisaged.Sometimes, therefore, it may be opportune to consider the entire room as the patient environment, allowing greater flexibility in the use of the spaces.

2,5 m

1,5 m

1,5 m 1,5 m

1,5 m

1,5 m

1,5 m1,5 m

1,5 m

1,5 m

1,5 m

1,5 m 1,5 m

IEC 60364-7-710 <Art. 710.2.8

Figure 2.10: Identification

of the patient environment

Can the patient be positioned in

a single predefined position?

Group 2

Room

No patient

environment

Group 1

Group 0

NO

YES

2.1.7


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.8

Medical IT System

Electrical system intended for supply of power supply to the group 2 medical locations.

The Medical IT System consists of an insulating transformer for medical use and a device for permanent earth insulation resistance monitoring.The insulating transformer provides two essential functions: to guarantee the continuity of operation in the event of an earth fault and to reduce the voltage to which the patient may be subjected so that it is within safety limits (and therefore the current to which the patient could be exposed, protecting him/her from the risk of microshock).Since a second indirect contact would be equivalent to a short circuit, with the consequent tripping of protection devices and a serious hazard for the patient, a device must be associated to the insulating transformer that can detect any reduction in insulation and signal the first earth fault.

Equipotential bonding

Panel with remote signals

Medical insulating

transformerInsulation

monitor

test pushbutton

Power supply

230 V

Medical IT System of the group 2

medical locations

mute pushbutton

test pushbutton

mute pushbutton

> IEC 60364-7-710 Art. 710.2.10

Figure 2.11: Medical IT System


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.9

Main distribution board

A board in the building which fulfils all the functions of a main electrical distribution for the supply building area assigned to it and where the voltage drop is measured for operating the safety services.

It is the switchboard powered by the main low voltage switchboard which in turn feeds the zone and department switchboards.It is intended for ordinary and safety distribution (power supply by an electricity-generating unit in the absence of the network). The following are installed in it: protection and cut-off devices, measuring instruments, and possibly an automatic network/generator unit commutator (which could, however, be inserted alternatively on the electricity generator unit switchboard).The voltage value below which the safety services are activated is measured on this switchboard.

MV switchboard

NETWORK

General LV switchboard

Main distribution board (of building)

Medical operators zone

switchboard

Quadro

UPS

Generator unit

switchboard

MT/BT

QDP

Q1

Q2 Q3 Q4 e Q5

Medical IT System

section not Medical IT

System

G

Generator unit

Surgery department

Operating Block

switchboard

Surgery room

switchboard

IEC 60364-7-710 <Art. 710.2.9

Figure 2.12: Example of star distribution of electrical energy in a

hospital structure


2

WH

Y IT

IS IM

PO

RTA

NT

TO

DE

SIG

N A

ND

IMP

LEM

EN

T A

SY

ST

EM

AC

CO

RD

ING

TO

TH

E S

TAN

DA

RD

S

2.1.9 continued

It is advisable: - that the main distribution board of the building and the department and zone switchboards

powered directly by the main distribution switchboard be located in a position protected against fire.

- to position the distribution switchboard for the building in appropriate rooms, not directly communicating with the environments intended for the public and not in proximity to combustible structures or to stores for combustible material.

Figure 2.13: Example of a main distribution switchboard


3Implementation of systems in medical locations

3.1

Area of application of the standardIn medical locations it is necessary to guarantee the safety of the medical personnel and in particular of the patients who may come into contact with electromedical devices; therefore specific safety prescriptions must be observed, in additional to the general prescriptions of IEC 60364-7-710, concerning both the devices and the systems. The safety of electrical systems in medical locations is the subject of section 710 of Standard 60364 which applies to hospitals, medical clinics, medical and dental studios, rooms for massage physiotherapy, and in all those environments, wherever they may be (for example, medical locations in the workplace or in buildings also intended for residential use), in which electromedical devices with parts applied to the patient are used. The prescriptions also apply to premises for aesthetic use.

3.2

Safety prescriptions for medical locationsThe hazard of electrocution may arise from direct contact with a live part of the circuit, or from indirect contact with a metal part, for example the metal body of a steriliser, which is not normally live, but which has become live due to an insulation malfunction.IEC 60364-7-710 allows the following protection systems against direct and indirect contact in medical locations.

Protection against direct contactFor protection against direct contact with live parts only insulation of the active parts or the segregation thereof through the use of barriers or casings with a protection level no less than IPXXD (or IP4X) for horizontals surfaces within reach are allowed, and IPXXB (or IP2X) in all the other cases.

Protection against indirect contactProtection against indirect contact in medical locations is based on the following provisions:a) Protection through automatic idisconnection of the power supply.b) Supplementary equipotential bonding for the conductive parts and the extraneous

conductive parts present in the patient environment, or which may enter the zone;c) Medical IT System;d) Use of equipment with Class II insulation;e) Systems with very low safety voltage (SELV and PELV).

IEC 60364-7-710 applies <to hospitals, clinics, medical and dental surgeries, rooms for massage physiotherapy,

beauty centres and veterinary surgeries


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Figure 3.1: Examples of type A and type B RCDs

Table 3.2: Maximum interruption times for TN-S systems

Table 3.1: Overview of protective measures against indirect contact

> IEC 60364-7-710 Art. 710.413.1.3

3.2 continued

Protective measures Group 1 Group 2

Automatic disconnection of the power supply

For all the circuits not powered by the Medical IT System

Medical IT System

Supplementary equipotential bonding

Resistance of conductors 0.2

Class II devices Connection of conductive parts to the equipotential bonding

Systems with very low safety voltage (SELV and PELV)

Connection of conductive parts to the equipotential bonding

a) Protection through automatic circuit breakingThis protection must be applied in a way that is compatible with the earth connection method used by the network (TN or TT) and bearing in mind that the value of the limit contact voltage UL, in the event of a malfunction, is reduced to 25 V (for the section of system in low voltage).

In TN systems it is prohibited to use a PEN conductor (TN-C scheme) downstream of the main distribution switchboard because this can cause disturbances and may constitute a fire hazard; therefore only the TN-S system is allowed. In these systems a dead short earth fault must cause the tripping of protection devices (usually automatic miniature circuit breakers) within the times specified in table 3.2.

Voltage U0 (phase-earth) (V)

Terminal circuits t (s)

Distribution circuits t (s)

120 0.4 5

230 0.2 5

400 0.06 5

The following relationship must be satisfied in TT systems:RE · Idn 25

where:RE is the earth resistance of the earth plate (in ohm);Idn is the highest nominal operating residual current of the RCDs that for protection of the system (in amperes).In group 1 medical locations, the standard requires protection only of the terminal circuits that supply sockets outlets with a rated current of up to 32 A, through the use of residual current device with Idn 30 mA, although residual current type protection of all the circuits is desirable. In group 2 medical premises it is mandatory for all circuits that are not powered by an Medical IT System to be protected by RCDs with Idn 30 mA (unless those circuits are supplying power to fixed devices positioned at a height above 2.5 m and which cannot enter the patient environment).

Choosing the Residual Current Device (RCD)Some loads, such as uninterruptable power supplies (UPS), personal computers, printers, electromedical equipment, for example devices for computerized axial tomography or magnetic resonance (RM) etc. incorporate electronic circuits which, in the event of an earth fault, cause currents with continuous components that can compromise the operation of the normal differential devices of the AC type for protecting power supply circuits (the indirect contact currents are not detected by the toroidal transformer).This is why group 1 and group 2 rooms are obliged, depending on the type of leakage current, to use type A RCDs, which can also intervene with pulsating unidirectional leaking currents or type B RCDs also capable of intervening with unidirectional pulsating and continuous leakage currents.In the case of power supply via three-phase UPS the product standard requires protection to be achieved by means of RCDs of type B.


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2 continued

Types of RCDs

Simbolo Tipo Applicazione Descrizione

ACGroup 1 or 2 rooms with TN distribution system

Only works only for earth fault alternating currents, applied instantaneously or increasing slowly

AGroup 2 rooms: lighting system circuit, radiological sockets, sockets for equipment outside by the patient environment

Works only for alternating and unidirectional pulsating earth fault currents, applied instantaneously or increasing slowly

B

Works for alternating, unidirectional pulsating and direct earth fault currents, applied instantaneously or increasing slowly

A unidirectional pulsating current is a current that assumes a value no greater than 6 mA for an interval of at least 150° of each period of the rated frequency (at 50 Hz: 8.33 ms).

b) Supplementary equipotential bondingIEC 60364-7-710 prescribes the implementation of main equipotential connections, at the base of each building, in order to guarantee the equipotentiality of all the extraneous conductive parts entering the same building, and of supplementary equipotential connections in the environments at greatest electrical risk.Group 1 and 2 medical locations are expressly covered by this prescription because the differences of potential between conductive parts and extraneous conductive parts and therefore the currents that could affect a patient in contact with such conductive parts are limited to the maximum with the additional equipotential connections.Each room for medical use must therefore be equipped with its own equipotential bonding bus bar to which the electrical devices and all the metallic parts that can close an electrical circuit to earth must be connected, so that if an indirect contact of a device (even external to the premises) occurs all the conductive parts and the extraneous conductive parts assume almost the same potential instantaneously (no significant difference of potential between the devices accessible to the patient).For group 2 medical locations, the equipotential bonding bus bar resistance shall not exceed 0.2 .

c) Medical IT SystemIt is well known that the RCD does not limit the residual current but the time that it remains (from 30 to 10 ms approximately); in this period of time, although very small, the voltage to the equipotential node can reach high values and the patient can be in serious danger if in contact with the conductive part of the faulty device and another conductive part or extraneous conductive part.For this reason, in group 2 medical locations with a microshock hazard the standard prescribes the use of an Medical IT System, together with the equipotential bonding bus bar, for all the circuits that supply power to:- medical electrical equipments located less than 2.5 m from the walking surface, or which

can enter the patient environment;- socket outletss (except for those that power devices with a consumption higher than 5

kVA and radiological devices).In fact the Medical IT System makes it possible to:- limit the indirect contact currents by containing the contact voltages;- reduce leakage currents;- guarantee continuity of service in the event of a first earth fault of a device.With the Medical IT System, the circuits branched to the secondary must be protected with fuses or thermomagnetic automatic circuit breakers, but not RCDs because the RCD would not be effective in this particular system.

d) Class II componentsMedical electric equipments too can be implemented with insulation in class II and carry the “double insulation” symbol.For these devices there is no obligation to connect them to earth if installed in ordinary or group 1 locations; instead they must be connected to the equipotential bonding bus bar (or to a sub-node) if used in group 2 medical locations.

“Double insulation” symbol

Obligation for <equipotential connections

IEC 60364-7-710 <Art. 710.413.1.2.2.1

Conditions that make <the use of a Medical IT

System mandatory


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Figure 3.2: Equipotential bonding bus bar consisting of a terminal bar

3.2 continued

e) Protection against direct and indirect contacts (SELV and PELV systems)The combined protection against direct and indirect contacts is assured by very low safety voltage which can be implemented with SELV (Safety Extra Low Voltage) and PELV (Protection Extra Low Voltage) systems, provided that their rated voltage is not higher than 25 V in alternating current and 60 V in non inverted direct current.The power supply must arrive from a safety transformer or from a battery and the SELV and PELV circuits must be installed in the manner prescribed by IEC 60364-4, clause 411.1.The active parts, if not adequately insulated, must be protected with a protection degree that is at least IP XXB and, for higher horizontal surfaces within reach (for example, beds, tables or other surfaces), at least IP XXD.The use of these systems in Group 2 rooms requires the following additional provisions: - the safety transformer must be powered at the primary by the Medical IT System if

devices that enter the “patient environment” are connected to SELV or PELV systems (a typical case is the power supply of the scialytic lamp if this is 25 V);

- the devices powered must be connected with the equipotentialisation system of the medical locations (equipotential node).

SELV and PELV systems are rarely used, except for supplying power to dedicated devices, such as scialytic lighting devices or infusion pumps.

3.2.1

Equipotential node

The function of the equipotential bonding bus bar is to galvanically interconnect all the conductive parts and extraneous conductive parts present or which could enter in the patient environment (fig. 3.2). In this way, if a conductive part malfunction occurs, all the conductive parts will have the same potential and the patient, who may be in contact with two or more conductive parts, is not subject to hazardous currents.The Standards prescribe the installation of an equipotential node bonding bus bar in each group 1 and 2 medical location.

The node can be implemented with a terminal bar or a copper bar with multiple holes (one for each conductor connected) and located on a wall inside or immediately outside the premises.The general rules apply in group 0 medical locations and therefore there is no equipotential bonding bus bar required, except, of course, for bath and shower rooms.

230 V

PE

SELV system

PELV system

230 V

PE possibleconnections


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.1 continued

The elements that may <cause differences on

potential must be connected to the

equipotential bonding bus bar, each with its

own conductor

(1) piping for hot and cold water, drains, oxygen, medical gases, air conditioning, plasterboard supporting structures, metal fixtures excluding the moving parts such as doors and openable windows

(2) since in conditions of use it can enter the patient environment

(3) only for group 2 rooms, also SELV and PELV devices

(4) apart from the earth contact of the plug sockets positioned above 2.5 m, used exclusively for supplying power to lighting devices, which must however be connected to the earth system

(5) in group 2 rooms(6) without electrical components

Table 3.3: Elements to be connected and not to be connected to the node

– the conductive parts and the extraneous conductive parts (1)

that are located in the patient environment, or which may enter it during use, including those installed at a height above 2.5 m, such as the conductive part from the scialytic device (2)

– the device protection conductors (3)

– the earth contacts of all the sockets of the premises, since they can supply power to devices that could be brought into the patient environment (4)

– the iron components of the reinforced concrete of the premises, when possible

– any metal screen placed between the windings of the medical insulating transformer (5)

– any metal screens intended to reduce electromagnetic fields

– any conductive grids located under the floor

– Non-electrical and fixed position operating tables unless these are intended to be earth insulated

– metal furniture units (6)

– metal parts of furnishings

Ele

ments

to b

e c

onnecte

d t

o t

he n

ode

Ele

ments

not

to

be c

onnecte

d


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.1 continued

Figure 3.3: Example of the elements to be connected to the equipotential bonding bus bar

In the hospital accommodation rooms (group 1 rooms), all the conductive parts and extraneous conductive parts and any screens against electromagnetic interference must be connected to the equipotential bonding bus bar, because the patient environment must be considered as extended to the entire room.If there are bathrooms or shower rooms functionally connected to the group 1 rooms and ordinarily used by the patient, these too must be equipotentialised through the local node.

not required if

H2O / medical gases

if possible

Network

Equipotential bonding bus bar

Patient environment


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.1 continued

Sub-nodesIn general cascaded connection is not allowed (sub-node), with the exception of metal piping and nearby plug sockets.Only one sub-node may be placed in the equipotential connection between a conductive part or extraneous conductive part and the equipotential node. It is also possible to have several intermediate nodes in the same premises as long as the aforementioned rule is satisfied.The in-out connection between sockets must be considered as a sub-node, and therefore cannot involve more than two sockets.

sub-node

sub-node

NOT ALLOWEDadditional sub-node

sub-node

equipotential bonding bus bar

equipotential bonding bus bar

sub-node

CORRECT

LEVEL 0

LEVEL 1

Figure 3.4: Correct and not allowed use of sub-nodes


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.1 continued

Cross-section of the conductors connected to the equipotential bonding bus barThe conductors that connect the extraneous conductive parts to the equipotential bonding bus bar are defined as equipotential conductors and must have a cross-section of no less than 6 mm2.The conductors that connect the conductive parts to the equipotential node are protection conductors (PE) and their cross-section must be established using the criteria specified by the general standard; in other words, it must be at least equal to that of the phase conductors.The cross-section of the conductor that connects a sub-node to the equipotential bonding bus bar must be at least equal to that of the conductor with the largest cross-section connected to the sub-node.

2.5 mm2

4 mm2

6 mm2

2.5 mm2

EQS 6 mm2

EQS 6 mm2

PE 10 mm2

10 mm2

PE

2.5 mm2

6 mm2

6 mm2 4 mm2

10 mm2

Sub-node

Sub-node

Sub-node

Equipotential bonding bus bar

PE

PE

The equipotential bonding bus bar must be connected to the main protection conductor of the earthing system with a conductor that has a cross-section equal at least to the greatest of those of the conductors under the same node.The protection conductor that acts as the building support must also have a cross-section that is not smaller.For group 2 medical locations, the resistance presented by the conductor and by the connections between an equipotential bonding bus bar and a conductive part or extraneous conductive part must not be greater than 0.2 .In the presence of sub-nodes, the resistance limit of 0.2 refers to the resistance of the total connection, also including the resistance of the sub-node.For group 1 medical locations it is enough to ensure only the electrical continuity of the conductors.Table 3.4 provides suggestions on the maximum length of protection and equipotential conductors so that their resistance will not exceed the limit indicated.

Cross-section of the conductor (mm2) 1.5 2.5 4 6 10

Maximum length (m) 12 19 31 47 78

Figure 3.5: Minimum cross-sections allowed for equipotential conductors

Table 3.4: Maximum length of the protection and equipotential conductor so that its resistance is no greater than 0.2


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Identification of the conductors to the equipotential bonding bus barThe equipotential bonding bus bar must be easy to access and to inspect; for example, it could be installed in a box built in to the wall.It must be possible to disconnect each of the conductors that meet up in the node individually (it is not allowed to connect two conductors to same the terminal) and they must be clearly identifiable in terms of function and origin (it is therefore advised to identify them at both ends) in order to facilitate testing.This identification can be implemented with markings that specify the above mentioned information or with numbers whose meaning must be specified in a list that is immediately available (for example, applied to the back of the box covering).

1

2

3

4

5

med

ical

ga

s

med

ical

ga

s

med

ical

ga

s

med

ical

ga

s

med

ical

ga

s

1

2

3

4

55

6

55

6

NOT ALLOWED

1= input to equipotential busbar

2= medical gas

3= hot and cold water

4= metallic shields

5= air conditioning

med

ical

ga

s

Figure 3.6: Identification of the

equipotential conductors by means

of numbering (top figure) and

nameplates (central figure)

3.2.1 continued


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.2

Medical IT SystemThe Medical IT system is prescribed by IEC 60364-7-710, which specifies the necessary characteristics of electrical distribution systems for special uses (Section 7) and for medical locations (710). The Medical IT system is powered with a specific insulating transformer for medical use that has a device for continuous monitoring of insulation as prescribed by IEC 61557-8.

Medical IT SystemClause 710.2.10 of IEC 60364-7-710 defines the Medical IT System as an electrical system that meets the requirements specified in article 710.413.1.5 as protection for electrical separation with permanent monitoring of the insulation resistance.The Medical IT System is not mandatory, but recommended in group 0 and 1 premises, while in group 2 medical locations it is mandatory in the patient environment, for socket outlets and for fixed equipment within reach.The Medical IT distribution system guarantees operational continuity even in the event of a first earth fault. In a traditional system, as in a domestic scenario, when a malfunction (short circuit, overload or dispersion) occurs, the relevant protection device is tripped. This type of tripping is not suitable for an operating theatre: in the case of a first fault the power supply must be maintained and not interrupted, which could be hazardous since it would involve the interruption of the activities of the doctor and the electrical equipment associated with the patient's health.

Insulation monitoing deviceAn Medical IT System must be powered with an insulating transformer for medical use and must be equipped with a device for permanent monitoring of the insulation, in accordance with IEC 61557-8 Standard. The insulation monitoring device must meet a number of basic requirements:– the a.c. internal impedance shall be at least 100 k ;– the test voltage shall not be greater than 25 V d.c.;– the injected current, even under fault conditions, shall not be greater than 1 mA peak;– indication shall take place at the latest when the insulation resistance has decreased to 50 k . A test device shall be providedIt must not be possible to disconnect the insulation monitoring device.

> The Medical IT system guarantees operational continuity in the case of first fault and guarantees the safety of the patient. It is always used in group 2 medical locations


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.2 continued

Medical insulating transformers

IEC 60364-7, in clause 710.512.1.6, specifies that:- the transformers must be installed inside or, in the immediate vicinity, outside the

medical locations- the secondary UN rated voltage of the transformers must not exceed 250 V AC- the transformers must comply with IEC 61558-2-15 in as far as applicable. In addition, they must conform to the following prescriptions:- the leakage current of the output winding to earth and the leakage current of the

enclosure, when measured in no-load condition and the transformer supplied at rated voltage and rated frequency, shall not exceed 0,5 mA.

- Single-phase transformers shall be used to form the medical IT systems for por-table and fixed equipment and the rated output shall not be less than 0,5 kVA and shall not exceed 10 kVA.

- if the supply of three-phase loads via an IT system is also required, a separate three-phase transformer shall be provided for this purpose with output line-to-line voltage not exceeding 250 V.

Other prescriptions for transformers: - They must be air cooled- They must have double or reinforced insulation between the windings, and between

these and the conductive part of the equipment;- A metal shield can be placed between the two windings to be connected to earth- The short circuit voltage must not exceed 3%- The no-load current of the primary must not exceed 3%- The peak current must not be greater than 12 times the rated current- The marking of the transformer must bear the symbol:

How to implement the Medical IT System and the parameters recommended by the StandardThe manufacture of insulating transformers must take account of compliance with Standard IEC 61558-1, which specifies the prescriptions relating to the technical requirements specifically for medical insulating transformers. The design must also observe the installation power restrictions established by IEC 60364-7-710, from 0.5 kVA to 10 kVA, with a voltage of 230 V for the primary and 230 V for the secondary. In fact, the use of limited power loads results in:- smaller systems- less users- lower probabilities of failure- easier maintenance- greater redundancy of the circuits- greater continuity of service

In addition, all the prescriptions imposed by IEC 60364-7-710 in this regard must be respected, from the presence of insulation monitoring device, to installation in a permanently monitored location, and the connection of the possible screen of the insulating transformer to the equipotential node in group 1 and group 2 medical locations.The Medical IT distribution system is shunted, in relation to the upstream power supply line, using an insulating transformer for medical use. This galvanically separates the ordinary circuits from the insulated line and eliminates the continuity of the protection conductor.The objective of the structure of these systems is to guarantee the continuation of medical operations after the first fault occurs. Such a situation must, however, be signalled, communicated and monitored in order to repair the first fault condition rapidly, and therefore to avoid a second failure

The characteristics <of these transformers

are specified in clause of IEC 60364-7-710

IEC 60364-7 and <insulating transformers

for medical use


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.2 continued

The operating principle of the Medical IT system is based on the fact that the circuit powered by the secondary of the insulating transformer is galvanically separated, when a conductive part first fault occurs due to a defect of the insulators in a load, the current cannot continue to flow in the phase conductors. In this situation all the electromedical devices are operational.The fault must not however persist for a long time because if a second fault were to taken place, the safety and functioning of the system would be compromised.

There is no hazardous current circulating on the PE and the user devices are functioning normally.

There are no hazardous currents flowing on the PE, but the first user device remains out of service.

Because of the current that flows on the PE, it is necessary to disconnect the power supply to the IT network since the obligation of protection cannot be met.

No fault

First fault

Second fault


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.2 continued

ABB’s technological leadership in the hospital sectorWith its H+LINE product line, ABB offers its expertise and technical experience in a sector, namely the hospital sector, that requires a very high degree of innovation and research, as well as a constant guarantee of safety and results.

TI medical insulating transformersThe medical insulating transformers from ABB provide the perfect solution to these requirements:in fact they combine Standards compliance with maximum performance and minimum dimensions. These small dimensions make it possible contain the costs for the switchboards in which they are to be located.The range consists of transformers with power consumption of 3, 5, 7.5 and 10 kVA, available with two PT100 temperature probes, on both the primary and the secondary. Its PT100 sensors, unlike the PTC type, are true temperature sensors and not simple thermal alarms that trip when preset limits are surpassed. PT100 sensors allow constant and precise monitoring of the temperature, which can be displayed by the ISOLTESTER insulation monitor. In addition, these sensors allow compensation of errors deriving from the intrinsic resistance of the temperature sensor cable itself: the error compensation is useful the sensor connection cables used are very long and the application requires high precision.An important parameter to evaluate in choosing a device of this type is the thermal insulation class, that is, how much the product may “heat up” when loaded, while remaining in conditions of safety. ABB transformers use a particular impregnation system, which allows maximum dissipation of heat, thanks to the exclusive vacuum-pressure technology.Lastly, the insulating transformer between the two windings has a metal screen that contributes in filtering network interference and the harmonic components generated by the power supply.

Technical characteristics of IT insulating transformers for medical use

Power kVA 3 5 7,5 10Primary voltage V 230 230 230 230Secondary voltage V 230 230 230 230Frequency Hz 50-60 50-60 50-60 50-60Secondary currents A 13 21.7 32.6 43.5Current of the external secondary delayed fuse T12,5 T20 T32 T40Thermal insulation class °C B 130 B130 F 155 F 155Dimensions mm 205x340x150 240x380x150 240x380x160 277x380x260Weight kg 29.5 44 50.5 73Plug-in current (peak value) < 12 times the rated currentEarth leakage current of the secondary winding and current of dispersion of the casing (both without load)

mA < 0.5

Maximum ambient temperature °C 40 40 40 40Reference standards IEC 61558-1 IEC 61558-2-15 IEC 62041Electrical class 1 1 1 1

TI insulating transformer for medical use ordering codes

Power KVA

PT100 Sensor

Description

Type

ABB Code BbN8012542EAN

3 - TI 3 2CSM110000R1541 2896005

5 - TI 5 2CSM120000R1541 2896104

7.5 - TI 7.5 2CSM130000R1541 2896203

10 - TI 10 2CSM140000R1541 2521204

3 TI 3-S 2CSM210000R15a1 2521402

5 TI 5-S 2CSM220000R1541 2521501

7.5 TI 7.5-S 2CSM230000R1541 2521600

10 TI 10-S 2CSM240000R1541 2521709

Figure 3.7: TI insulating transformer


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.3

Insulation monitoring deviceA current originating outside the electrical system, for example an earth leakage current circulating in an electrical device, can cause serious damage because of the greater vulnerability of the patient: in surgical conditions, a current of just tens of microamperes is enough to cause ventricular fibrillation, which is not the case under “normal conditions”, where this type of value is more acceptable.The leakage current can be classified into three different types:- earth leakage current (of the protection conductor) - Fig. 3.8.A;- contact current, in other words the current that crosses the person in contact with the

live casing due to a malfunction of the insulators - Fig. 3.8.B;- leakage current in the catheterised patient and which flows to earth - Fig. 3.8.C.

Fig. 3.8.A Fig. 3.8.B Fig. 3.8.C

For each of these there are allowable values that in turn depend on the type of electromedical device as established by IEC 60601-1 “Medical electrical equipment - General requirements for basic safety and essential performance” which applies to medical electrical equipments intended for use by qualified personnel, or under their supervision, in the environment surrounding the patient, or in relation with the patient, in such a way that they directly influence the safety of persons and animals in that environment. The Standard specifies the prescriptions for the transport, storage, commissioning, use and maintenance of such devices in the environmental conditions specified in the Standard or by the manufacturer, or prescribed in particular Standards. The purpose is to establish a satisfactory level of safety for all the electromedical devices used in an environment surrounding the patient and to serve as a basis for the safety prescriptions of specific standards for the individual types of devices.

Device with parts applied of type B Less safe

Device with parts applied of type BF Safer

Device with parts applied of type CF Even safer

Leakage current [mA]

Conditions Type of part applied

B BF CF

To earth (1) Normal 5 5 5

First fault 10 10 10

Contact Normal 0.1 0.1 0.1

First fault 0.5 0.5 0.5

In the patient (2) Normal 0.1 0.1 0.01

First fault 0.5 0.5 0.05

(1) Changed in comparison to earlier editions of IEC 60601-1.(2) In the case of direct current the limits for Type B and BF applied parts are one tenth of

those specified. In addition, higher values are allowed for particular conditions.

Figure 3.8: Examples of situations that cause leakage currents

Table 3.6: Permissible values for leakage currents (IEC 60601-1)

Table 3.5: Types of medical electrical equipments with applied parts


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.3 continued

Characteristics of the insulation monitoring devicePermanent monitoring of the first fault to earth must be carried out using an appropriate insulation monitoring device inserted between the secondary of the insulating transformer and the protection conductor. For each insulating transformer for medical use there must be an insulation monitoring device in order to immediately signal a possible first fault and to allow the appropriate maintenance operations necessary to restore the system to optimal conditions. The monitoring device must comply with the provisions of IEC 61557-8 and must have the following additional characteristics if installed in a medical environment:- internal impedance: not less than 100 k (measured between system terminals and

earth);- test voltage: 25 V DC max (between the measurement terminals);- test current: 1 mA DC max (between the system and earth, also in the case of a

malfunction);- impossibility of deactivation.When the resistance of earth insulation drops below 50 k the device must signal the malfunction. It must, however, be possible to verify the actual operational capacity of the instrument by means of a test circuit

Luminous indications and acoustic signalsThe insulation monitoring system must be equipped with acoustic and luminous signals. This function is performed by a remote signalling panel, directly connected to the insulation monitor. This device makes it possible to:- carry the signal to several parts of the building;- make the insulation monitor signal immediately visible which may be installed in places

inadequately staffed by the appropriate personnel (technical rooms, corridors…);- identify the type of alarm in progress (low insulation, overload etc).These are the signals provided:- green indicator light (normal operation);- yellow indicator light (insulation has dropped below 50 k );- an acoustic signal.It must not be possible to switch off or deactivate the yellow indicator light while the malfunction remains on the system.This is the sequence of signals in the case of a malfunction:- the acoustic alarm is put into operation;- the acoustic buzzer is silenced (continuous yellow indicator light);- the yellow indicator light switches off as soon as normal conditions are restored (after

the malfunction condition has been resolved);- interruption of the connection between the Medical IT system or earth and the monitoring

device is signalled.

Lastly, here are a number of design suggestions:It is not necessary to install an insulation monitoring device if the transformer only supplies power to a single medical electrical equipment; in this case, in fact, the probability of an indirect contact (and, even more so, of a second indirect contact) is remote. In addition, the short circuit deriving from the second indirect contact would not be able to create hazardous voltages on the conductive parts of other devices.The optical and acoustic alarm system should not be installed in just one location; this allows the alarm to be perceived also by those present in contiguous premises.

IEC 61557-8 <

IEC 60364-7 <Art. 710.512

Figure 3.9: QSD remote signalling panels allow medical personnel

to be immediately aware of malfunction situations

Design instructions <


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.4

Insulation monitoring devices for 230 V linesISOLTESTER is the insulation monitor manufactured by ABB and suitable for insulated neutral MEDICAL IT networks for group 2 medical locations with an MEDICAL IT power supply system.ISOLTESTER monitors the earth insulation of the electrical power supply grid and the electrical or thermal overloading of the transformer, according to the parameters required and recommended by international standards:- IEC 61557-8- IEC 60364-7-710- UNE 20615.

Insulation resistance is monitored by applying a measuring signal in direct current between the insulated line and earth, and measuring the earth leakage generated.A digital filter inserted in the instrument guarantees effective measurement even in the presence of interference and harmonic components.

The four selection keys and LCD display make it easy to program the device, setting the tripping thresholds without any possibility of error (the configurable values are within the range of values specified by the Standards).ISOLTESTER allows monitoring of the electrical and thermal overload of the medical insulating transformer by managing two distinct temperature thresholds coming from both PT100 and PTC sensors.Temperature monitoring makes it possible to monitor overloading of the transformer and to avoid the automatic miniature circuit breaker downstream of the secondary.All malfunction conditions are remotised thanks to a connection with (up to four) QSD remote signalling panels, thereby guaranteeing adequate and prompt technical supervision.Finally, the Error-Link Fail system executes self-diagnosis of the device by checking that the wiring at the heads of the terminals is present and correct: this excludes the possibility of having the group 2 medical room in operation without the supervision of the insulation monitor.

ISOLTESTER-DIG-PLUS adopts a codified signal which guarantees the reliability of the measurement in any operational condition, even in the presence of serious network interference generated by the electronic equipment in the room. In addition, it is equipped with an RS485 serial port, thanks to which the device can be perfectly integrated with PLC/PC type communication systems by means of the ModbusRTU protocol. More extensive monitoring is possible because network minimum and maximum values are managed, which help in diagnosis of the system in the case of a failure. Lastly, a programmable relay allows complete control of any alarm condition detected.

Figure 3.10: QSO wall-mounted

switchboard

> Reliable measurement in all conditions

> Simple programming with four keys

- Keep the keys – and SET pressed to enter “installation setup” and define the parameters monitored

- Keep the SET key pressed to enter “adjustment setup” and define the threshold values

2 mediccal al locations

Fi

sw


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Technical characteristics of ISOLTESTER-DIG-RZ

Supply voltage 110 - 230 V/50-60 Hz

Network voltage to be measured

24÷230 V AC

Maximum voltage measurement

24 V

Maximum current measurement

1 mA

Insulation voltage 2.5 kV/60 sec.

Type of monitoring signal continuous component with digital filter

Measurements insulation measurement range 0÷999 k /HIGH resolution 1 k temperature measurement by thermal probe type PT100 with 2 or 3 wires -0÷250° C, precision 2% current measurement by A.T., external with secondary 5 A, precision 2% (ratio value selectable 1÷200) impedance measurement 0÷999 k /HIGH resolution 1 k (test signal 2500 Hz)

Activation thresholds low insulation 50÷500 k , precision 5%, hysteresis 5%, configurable delay overtemperature 0÷200 °C, precision 2% current overload 1÷999 A, precision 2% low impedance (deactivatable) device not connected to the line (link fail)

Outputs available up to maximum of 2 panels at a distance QSD for signalling auxiliary relay output NO-C-NC, 5 A, 250 V AC

Displays insulation resistance value with signalling of a value below the scale and dead short earth fault temperature value measured 0÷200 °C for trunking 1 temperature value measured 0÷200 °C for trunking 2 current value measured 0÷999 A insulation impedance value programming parameters absence of device connection to line (link fail) relay output status

Connections maximum connectable cross section 2.5 mm2

Operating temperature -10...60 °CStorage temperature -25...70 °C, humidity < 90%Dimensions 6 DIN modulesWeight 0.5 kgCasing self-extinguishing plastic container for mounting on

35 mm DIN rail, with transparent front protection cover with lead seal

Protection degree IP20Power consumption 5 VA

Reference standards IEC 60364-7-710, IEC 61557-8, EN 60255-6, UNE 20615

ISOLTESTER-DIG-RZ Ordering Codes

Description

Type


ISOLTESTER-DIG-RZ 2CSM244000R1501 884507

3.2.4 continued

6 modules

105

90

56

90 45

44

61

Overall dimensions


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Technical characteristics of ISOLTESTER-DIG-PLUS

Supply voltage 110 - 230 V/50-60 HzNetwork voltage to be measured

24÷230 V AC/DC

Maximum voltage measurement

24 V

Maximum current measurement

1 mA

Insulation voltage 2.5 kV/60 sec.

Type of monitoring signal codified compound signal Measurements taken insulation measurement range 0÷999 k /HIGH resolution

1 k temperature measurement by thermal probe type PT100 with 2 or 3 wires -0÷250° C, precision 2% current measurement by A.T., external with secondary 5 A, precision 2% (ratio value selectable 1÷200)impedance measurement 0÷999 k /HIGH resolution 1 k (compound variable signal)

Activation thresholds low insulation 50÷500 k , precision 5%, hysteresis 5%, configurable delay overtemperature 0÷200 °C, precision 2% current overload 1÷999 A, precision 2% low impedance (deactivatable) device not connected to the line (link fail)

Outputs available up to a maximum of 4 QSD panels for remote signallingprogrammable auxiliary relay output NO-C-NC, 5 A, 250 V AC R S 485 serial output, standard Modbus RTU protocol

Displays insulation resistance value with signalling of a value below the scale and dead short earth fault temperature value measured 0÷200 °C for trunking 1 temperature value measured 0÷200 °C for trunking 2 current value measured 0÷999 A insulation impedance value value of line earth capacity programming parameters absence of device connection to line (link fail) relay output status storage of min. value insulation and max temperature and current

Connections maximum connectable cross section 2.5 mm2

Operating temperature -10...60 °CStorage temperature -25...70 °C, humidity < 90%Dimensions 6 DIN modulesWeight 0.5 kgCasing self-extinguishing plastic container for mounting on

35 mm DIN rail, with transparent front protection cover with lead seal

Protection degree IP20Power consumption 5 VA

Reference standards IEC 60364-7-710, IEC 61557-8, EN 60255-6, UNE 20615

ISOLTESTER-DIG-PLUS Ordering Codes

Advanced functions Description

Type


RS485, Min/Max values, programmable relay

ISOLTESTER-DIG-PLUS 2CSM341000R1501 884606

3.2.4 continued

6 modules

105

90

56

90 45

44

61

Overall dimensions


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.4 continued

Operation of the front panel operators

5432167

8

9 10 11 12 13

Benefits of ISOLTESTER- ISOLTESTER is designed specifically for the hospital environment;- a single device allows control of the electrical and thermal parameters;- its flexibility allows the activation thresholds to be adjusted for all the values monitored;- there is high tolerance for network interference;- it is the recognised standard for monitoring hospital insulation;- measurement and display of resistance, primary/secondary temperature, impedance,

overcurrent;- RS485 serial communication port with ModbusRTU protocol (PLUS version);- management of maximum and minimum parameters (PLUS version);- insensitivity to network disturbance and ripples (PLUS version).

1 3 digit display2 Green LED, SET: instrument

programming status3 Yellow LED, Alarm: alarm for a

parameter value outside the threshold4 Red LED, Output Relay: auxiliary relay

status5 Red LED, Error / Link Fail: alarm for

internal failure, no connection to the line to be monitored, PT100 temperature probe open or in short-circuit

6 Red LED, R: insulation resistance (k )7 Red LED, Z: insulation impedance (only

for ISOLTESTER-DIG-PLUS: insulation impedance and capacity of the line)

8 Red LED, T1: transformer temperature9 Red LED, T2: 2nd sensor temperature10 Red LED, I: line current11 +/- | UP/DOWN: selection of the

parameter to display, adjustment of the settings and display of the maximum and minimum values stored (only for ISOLTESTER-DIG-PLUS)

12 RESET | SET: access to programming of the instrument, silencing of alarms and deletion of stored values

13 TEST | ENTER: testing of the instrument and the remote signalling panels and confirmation of SETUP settings


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.4 continued

ISOLTESTER-DIG wiring diagrams

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

RS485(only PLUS

version)

CT .../5 AOut

Link FailInsulationcontrol QSD-DIG 230/24

ISOLTESTER-DIG-RZLLISOLTESTER-DIG-PLUSLL

V aux.*115 V 115 V

1 2 3 4 5 6 7 8 9 10 11

QSD-DIG 230/24

V aux. 230 V a.c.

Insulating transformer with PC

IT-M Load

Oth

er Q

SD-D

IG

1 2 3 4

V aux.*115 V 115 V

V aux. 115 V a.c.

PE

PCCL

N

SS

PT100 PT1002 1

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

RS485

PT100 PT1002 1 CT .../5 A

Out

QSD-DIG 230/24


V aux.*115 V 115 V

1 2 3 4 5 6 7 8 9 10 11

QSD-DIG 230/24

V aux. 230 V a.c.

IT-M Load

Oth

er Q

SD-D

IG

PE

L

N

SS

(only PLUSversion)

Link FailInsulationcontrol

Insulating transformer without PC

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

RS485(only PLUS

version)

CT .../5 A

Out.

QSD-DIG 230/24


V aux.*115 V 115 V

1 2 3 4 5 6 7 8 9 10 11

QSD-DIG 230/24

V aux. 230 V a.c.

IT-M Load

Oth

er Q

SD-D

IG

PE

N

L1

SS

L3

L2

PT100 PT1002 1

Link FailInsulationcontrol

Insulating transformer

* connection of temperature probes and ammetric transformer is optional

With transformer with central socket (PC)

With transformer without central socket (PC)

With three-phase transformer


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.5

Insulation monitoring devices for 24 V SELV circuitsSELVTESTER-24 is an earth insulation tester for SELV 24 V AC/DC circuits, particularly recommended for installation in medical locations in which 24 V and 230 V lines exist. The systematic and continuous monitoring of the low voltage line in these environments is recommended by IEC 60364-7-710 precisely because a failure or a short circuit could transfer a potential of more than 250 V with consequent damage to persons and things.

CharacteristicsSELVTESTER-24 monitors the insulation resistance of dedicated 24 V AC/DC circuits for powering a scialytic lamp.It is important to monitor the insulation of the scialytic lamp because conductors could become detached and enter into contact with the metal structure while the lamp is being manoeuvred.SELVTESTER-24 measures the variation of the potential of the two network polarities in relation to the earth, and signals a decrease in resistance below a predefined value, allowing immediate interception of the malfunction. In a direct current situation it is also possible to discern the polarity involved in the failure. The output signal can be carried remotely in rooms with the greatest medical staff presence thanks to remote signalling panels called QSD-DIG 230/24.The front of the SELVTESTER-24 includes a test pushbutton, status indicator and two LEDs for alarms caused by low insulation. Microswitches allow the activation threshold to be varied (10….50 k ). The TEST pushbutton performs the periodic correct operation test.

Technical characteristics of SELVTESTER

Network voltage and auxiliary power supply

24 V 50-60 Hz/DC ± 20%

Max. loss 3 VA

Measurement current max. 0.5 mA

Internal impedance 50 k

Activation threshold setting adjustable 10 ÷ 50 k (4 levels by means of microswitches)

Activation delay approx. 1 s

Signals ON LED, ALARM + LED, ALARM - LED

OutputFor max. 2 QSD-DIG230/24 remote panelsMax. 24 V 1 A

Operating temperatureStorage temperature

-10 ÷ 60 °C-20 ÷ 70 °C

Relative humidity 95%

Insulation test 2.5 kV 60 s / 4 kV imp. 1.2/50 μs

Cross section of terminals 4 mm2

Protection degree IP40 front panel with cover / IP20 container

Modules 3

Weight 200 g approx.

Reference standards safety IEC 61010-1product IEC 60364-7-710electromagnetic compatibility IEC 61326-1

SELVTESTER-24 Ordering Codes

Monitored network Description

Type


SELV insulated line 24 V AC/DC

SELVTESTER-24 2CSM211000R1511 884705

52,5

3 modules

85,5

44

58

85,5

45

Overall dimensions


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.5 continued

1 2

3

4

Benefits of SELVTESTER- Overall dimensions of only three modules- Immediate installation;- Setting of the activation threshold to the most commonly used value;- Recognition of the faulty pole when operating under direct current.

Wiring diagrams


IT-M Load

Oth

er Q

SD-2

30/2

4-C

PE

L(+)

N(-)

SS

1 2 3 C1 C2 C3 C4 X Y Z

QSD-DIG 230/24

1 2 3 4 5 6 7 8 9 10 11

SELVTESTER-24LL

1 Green LED ONIndication that the instrument is functioning

2 Yellow ALARM LEDsLow insulation alarm signal; in the case of a line to be monitored, with alternating current the two LEDs light up, whereas with direct current only the LED of the polarity below the activation threshold lights up.

3 Test pushbuttonInstrument function test

4 MicroswitchesThe front microswitches allow the threshold to be set in the range 10 to 50 k , as shown in the diagram.


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.6

QSD remote signalling panelsIt ought to be possible to send an alarm caused by a possible malfunction from a distance, so that it is immediately obvious to medical personnel and specialized technicians.The QSD remote signalling panels also report alarm signals relating to a low insulation situation or in the case of electrical or thermal overload of the transformer, making it possible to identify the type of fault.

CharacteristicsQSD-DIG 230/24 control panels can be installed easily in universal flush-mounted boxes with three modules. They have a test pushbutton for periodically checking their operation and a second pushbutton that allows the simultaneous silencing of the acoustic signal of all the panels that may be connected to the same ISOLTESTER insulation monitoring device.With QSD-DIG 230/24 it is possible to distinguish, even remotely, the type of alarm; in other words whether it is caused, for example, by low resistance, an overload or an overcurrent (identification of the malfunction type). QSD-DIG 230/24 was designed to be fully compatible with all ABB insulation monitors for 230 and 24 V lines, both currently manufactured models and earlier versions:

Type of line monitored 230 V 24 V

insulation monitoring devicesISOLTESTER-DIG-RZISOLTESTER-DIG-PLUS

SELVTESTER-24

Phased-out insulation monitoring devices

ISOLTESTER-RZ ISOLTESTER-C

SELVTESTER-C

Wiring can be carried out with a common 0.35 mm2 cable, which guarantees signal cover up to a distance of 300 m.QSD-DIG 230/24 conforms to the following international reference standards:- IEC 612010-1;- IEC 61557/8;- IEC 60364-7-710;- UNE 20615;- IEC 61326-1 (Electromagnetic compatibility).

Technical characteristics QSD-DIG 230/24

Signals

green LED network, red LED overload, yellow LED faultbuzzer 2400 Hzintermitting 2 Hz dB

Pushbuttons test (TEST), acoustic silencing (MUTE)

Cross section of terminals 2.5 mm2

Protection degree IP30

Installation universal flush-mounted 3 modules box

Weight 200 g

Operating temperature -10 ÷ 60 °C, max humidity 95%

Storage temperature -25 ÷ +80 °C

Insulation 2500 Vrms 50 Hz per 60 s

Minimum cross-section of the cable 0.35 mm2 (300 m max)

Reference standards

safety IEC 61010-1 product IEC 61557-8 / IEC 60364-7-710 IEC 60364-7-710 UNE 20615 electromagnetic compatibility IEC 61326-1

QSD-DIG 230/24 Ordering Codes

Compatibility Description Type


Universal QSD-DIG 230/24 2CSM273063R1521 730637

A single panel <for universal

remote signalling

Reference standards <for QSD

121

78

17

55

78

Overall dimensions


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.2.6 continued

3

4

1

2 5

Advantages of the product- Small dimensions- Can be installed in a universal flush mounted box- Immediate recognition of the type of malfunction- Simultaneous silencing of multiple signalling panels- Operational efficiency

Wiring diagrams

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

RS485(only PLUS

version)

CT .../5 AOut

Link FailInsulation control QSD-DIG 230/24


V aux.*115 V 115 V

1 2 3 4 5 6 7 8 9 10 11

QSD-DIG 230/24

V aux. 230 V a.c.

Insulating transformer with PC

IT-M Load

Oth

er Q

SD-D

IG

1 2 3 4

V aux.*115 V 115 V

V aux. 115 V a.c.

PE

PCCL

N

SS

PT100 PT1002 1

ISOLTESTER-DIG

1 Test pushbutton2 Acoustic silencer pushbutton3 Green network LED4 Overload alarm red LED5 Malfunction alarm yellow LED


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

LF-PE

1 2 3 4 5 6 7 82 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18LF-L VC-L VC-PEEAUX-L11 AUX-011 COM-P V-PFAULT

Vaux:* Pannellocontrollo remoto

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Out

ISOLTESTER- C

1 2 3 43 5 6 7 8 9TEST+TEST-

10 11ACKACUS OVER COM-PV-P FAULTT

QSD-DIG 230/24

PE

PC

SS

IT-M LOAD

Vaux: 230Va.c.

230V

L

N

OTHERQSD-DIG 230/24

COM-S F-S TEST-SR-NO R-CR-NC


Link FailInsulation control

1 2 3 4 5 6 7 83 4 5 6 7 9PE

10 11V-

SELVTESTER-24

V+

PE

SS

IT-M LOAD


L(+)

N(-)

QSD-DIG 230/24

1 2 3 4 5 6 7 82 3 4 5 6 7 9

OTHERQSD-DIG 230/24

OUT-UU NO OUT-UU NCOUT-UU C10 11

TEST++TEST-SACKACUS OVER COMPV-P FAULTLCOM-S F-S TEST-SS

3.2.6 continued

SELVTESTER-24

ISOLTESTER-C ISOLTESTER-DIG-RZ


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3

Implementation of the electrical systemTo implement the electrical system in medical locations both the general prescriptions of IEC 60364 as well as the specific prescriptions of section 710, included in the seventh part, must be observed.The main best technique rules are specified below concerning switchboards for the distribution of energy within a hospital structure and the installation of systems in group 2 rooms.

3.3.1

Electrical switchboardsAll the electrical switchboards must conform to the safety prescriptions of Standards IEC 60439-1 and 3.In environments for medical use, depending on their size, is may be necessary to use the following types of electrical switchboards (fig. 3.11):- general low voltage (QGBT);- for main distribution in the building (QDPE);- for department (QR);- for surgery room (QSO).

Operat.theatreA Operat.

theatreB

QR

QDPE

QR

QR

Depart. C

QGBT

QDPE

QR

QR

QSOQSO

QR

QDPE

MV/LV main

switchboard

Entrance - Offices

Pavilion 1

Pavilion 2

Depart. B

Depart. A

Depart. F

Depart. D

The main switchboard and the distribution switchboard for the building should be located in specific rooms, not directly communicating with the environments intended for the public and not in proximity to combustible structures or stores for combustible material.

Protection degree of switchboards

Per la protezione contro i contatti diretti Protezione contro le influenze esterne

IPXXD(IP4X)

for horizontal surfaces within reach IPX4in rooms where fluids are normally spilt

IPXXB(IP2X)

for all the other cases IPX5in rooms for the use of jets that must be cleaned with water

Figure 3.11: Representation of the star distribution system used in healthcare structures

> Types of electrical switchboards


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.1 continued

General LV switchboardSwitchboard for ordinary energy distribution (from the network) in which the following may, for example, be installed:- general protection and sectioning devices;- measuring instruments and remote monitoring devices;- protection devices for the lines that supply power, for example, to: auxiliary cabinet

services;the auxiliary electricity-generator unit services; the main distribution lines to the buildings; the distribution lines of services external to the buildings; the technological stations (air conditioning system, thermal and water station).

Main distribution switchboard of the buildingSwitchboard for ordinary and safety distribution (through the electricity-generating unit) in which the following are installed:- general protection and sectioning devices;- measuring instruments and remote monitoring devices;- protection devices, preferably suitable for sectioning, for the lines that supply power to

appliances that require power from an electricity-generating unit (fire-prevention system, lifting systems).

Department switchboardsThe department switchboards can be the same as the main switchboards of the building.If these switchboards are located inside the pavilion or department, they should preferably be located in a special room. They are recommended to have glass (or transparent plastic material) doors to facilitate checking the state of the devices.The destinations of the lines leaving the switchboard depend on the functions that the department carries out.

Switchboards for surgery roomsFor group 2 surgery rooms, in addition to the switchboard for the power supply of the ordinary circuits, a switchboard for supplying power to the Medical IT system is also necessary (fig. 3.12). It is also allowed to use a single switchboard that groups the Medical IT system equipment and the power supply equipment for all the other appliances into two distinct sections. In the absence of the ordinary power supply, the switchboard must commutated onto the safety power supply provided by an uninterruptible power supply (UPS).

Socket group

Socket group

Socket group

Diaphano-scope

Anae-sthetist’s pensile

sockets (1)

Surgeon’s pensile

sockets (1)

Scialytic lamp

power supply

Fixed operating

table

Reserve

1 2 3

24 V Line

5 QSD230/24-C

4

3

3

Id

Auxiliary line

2

QSD-DIG230

6

(1) The sockets of the anaesthetist and surgeon pensiles are powered by multiple lines

1 Surge arrester2 Insulating transformer3 Temperature probe PT1004 Insulation monitoring device for 230 V

circuit5 Insulation monitoring device for 24 V

circuit6 Transformer 220/24 V - 1 kVA

Figure 3.12: Switchboard for the Medical IT system power supply.


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.1 continued

In this way the continuity of service of all the Medical IT powered devices in the premises is improved and high quality power supply for the electromedical devices particularly sensitive to the voltage and frequencies is guaranteed.In the case of a single switchboard, subdivided into two sections, the following components are installed:- a general sectioning device;- RCDs on each outbound connection and with Idn 30 mA, and of type A or B for the

ordinary power supply;- a device for protection against overcurrents upstream of the insulating transformer;- possibly a circuit-breaker downstream of the insulating transformer for protection against

the overloads in the case where there are no temperature sensors on the insulating transformer

- the Medical IT system devices (insulating transformer, permanent insulation monitoring device with optical and acoustic signalling).

- protection devices against overcurrents of the lines that supply power to the plug sockets and of any other fixed devices of the Medical IT system.

The equipotential node of the switchboard could be used as the equipotential node of the premises if it complies with the prescriptions of the standards.

Choice of power consumption of the medical insulating transformerThe power consumption of the insulating transformer depends on the type of premises in question, the power consumption of the connected loads and on maintenance and continuity of service requirements.On average, the Medical IT system supplies power to at least 6 groups of sockets:- 2 socket groups available to the surgeon- 2 socket groups available to the anaesthetist- 2 wall-mounted socket groups.For very large cardiac surgery rooms power consumption of up to 15 kVA can be envisaged, and therefore two 10 kVA insulating transformers are used so as to have a surplus of power that will allow for future expansion. One transformer can supply power to wall-mounted sockets while the other can power the sockets of the pensiles.In normal operating rooms or outpatient departments the power of the transformer drops to 7.5 - 5 - 3.5 kVA.In any case, it is always preferable to overestimate power consumption to enable future expansion without having to modify the system.

Section “E”(Emergency)

Section “S”(Safety)


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.1 continued

Electrical switchboard for medical locations

QSO switchboards for operating theatres represent the ideal solution for distribution within group 2 medical locations. Four sizes are available: S, M, L, and XL. ABB provides, for its switchboards for operating theatres, the declaration of conformity required to commission the system, ensuring the installer that the system is built in compliance with technical standards.

Power KVA

IT-M linesect. no.

SELVline24 V

Order detailsType code

Order code Bbn801254EAN

Price 1 piece

Pricegroup

Weight1 piecekg

Packunitpc.

S series switchboards for medical locationsApplications: surgery clinics, post-op recovery rooms, analysis laboratories, dental offices, veterinary clinics

3 2x10A+3x16A - QSO 3S Classic 2CSM261122R1551 2611226 113 15 2x10A+3x16A - QSO 5S Classic 2CSM273692R1551 2736929 128 13 2x10A+5x16A 1x25A QSO 3S Premium 2CSM273602R1551 2736028 150 15 2x10A+5x16A 1x25A QSO 5S Premium 2CSM273682R1551 2736820 130 1

M series switchboards for medical locationsApplications: Day hospital rooms, medium sized operating theatres, ICU rooms

3 3x10A+7x16A - QSO 3M Classic 2CSM273592R1551 2735922 180 15 3x10A+7x16A - QSO 5M Classic 2CSM273672R1551 2736721 195 17,5 3x10A+7x16A - QSO 7,5M Classic 2CSM273582R1551 2735823 202 13 6x10A+8x16A 1x25A QSO 3M Premium 2CSM273662R1551 2736622 181 15 6x10A+8x16A 1x25A QSO 5M Premium 2CSM273572R1551 2735724 196 17,5 6x10A+8x16A 1x25A QSO 7,5M Premium 2CSM273652R1551 2736523 202 1

L series switchboards for medical locationsApplications: operating theatres, intensive care rooms, cardiac operating rooms

10 6x10A+9x16A - QSO 10L Classic 2CSM273562R1551 2735625 244 17,5 6x10A+11x16A+1x32A 2x25A QSO 7,5L Premium 2CSM273642R1551 2736424 222 110 6x10A+11x16A+1x32A 2x25A QSO 10L Premium 2CSM273552R1551 2735526 248 1

XL series switchboards for medical locationsApplications: resuscitation, intensive care, long term care

7,5+7,5 12x10A+22x16A+2x32A 4x25A QSO 7,5XL Premium 2CSM273632R1551 2736325 379 110+10 12x10A+22x16A+2x32A 4x25A QSO 10XL Premium 2CSM273542R1551 2735427 429 1

Technical features

QSO wall type QSO floor type

Rated operational voltage (Ue ) 230 V ~ ± 15%

Rated power frequency 50 - 60 Hz

Number of phases 1 + N ~⁄ PE

Rated voltage of auxiliary service circuits 24 - 230 V ~

Rated insulation voltage (Ul) 300 V - *2500 V

Earthing system TT / TN-S

Maximum prospective short circuit current to the input terminals (Icc)

10 kA RMS Sym ***

Max. altitude 2000 m s.l.m.

Pollution degree 1 **

Degree of protection against impacts (IK code) EN 50102 I

K 09 (5 kg - 200 mm)

Degree of relative humidity at temperature °C 50% with max. temp. +40 °C

Ambient air temperature - operation -5 °C - +55 °C

Ambient air temperature - transport and storage -25 °C - +40 °C

Degree of protection EN 60529 QSO 3S Classic IP 40 QSO 3M Classic IP 54

QSO 5S Classic IP 40 QSO 5M Classic IP 54

QSO 3S Premium IP 40 QSO 5M Premium IP 54

QSO 5S Premium IP 40 QSO 7.5M Premium IP 54

QSO 10L Classic IP 54

QSO 7.5L Premium IP 54

QSO 10L Premium IP 54

QSO 7.5XL Premium IP 54

QSO 10XL Premium IP 54

* Dielectric strength test voltage. ** Corresponds to no pollution or only dry and non-conductive pollution.*** Value conditioned by upstream coordination with NH 00 100A gL-gG fuses


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.2

SMISSLINE - Pluggable System. Keeps downtime to a minimum SMISSLINE allowed a high maintenance of electrical systems. Wherever availability is necessary in 365 days at 24 hours a day the pluggable system gives a maximum on Flexibility.SMISSLINE protection devices are simply snapped into a plug-in socket system. The arduous task of power supply and connection is done. In addition to savings in time and money, another advantage of the system is the quick and easy exchangeability of the devices. If the corresponding spare capacity is planned, subsequent expansion consists merely of plugging in and connecting additional devices.

Equipment AvailabilityAdditions, expansions and modifications of panel boards are easily done thanks to the modular structure of this system. Costs and downtime are limited to a minimum.The SMISSLINE plug-in system really comes into its own when safety, availability and versatility are essential requirements in structures.

System Overview

7

3

8

4

58

25

10

1

1

2

69

12

12

24

22

23

28

18

3 29 26

11

3031

30

27

24

28

21

1319

20

17

16

15

14

2624

1 Supply terminal2 Incoming terminal block with a

max. current rating of 160 A 50 mm2 (2 x 25 mm2) + 2 x 10 mm2 (LA, LB)

3 Cover for incoming terminal block4 Supply cable5 Surge arrester OVR4046 RCBO FS4017 Residual-current circuit breaker F4048 Miniature circuit breaker S401 M9 Signal contact10 Plug contacts11 DIN adaptor12 Spare way cover13 Device latch14 Busbar L3 or DC +, –15 Busbar L2 or DC +, –16 Busbar L1 or DC +, –17 Busbar N18 Sockets, 8-module and 6-module19 Auxiliary busbar LA20 Auxiliary busbar LB21 Busbar N, external22 Busbar PE, external23 Additional socket24 N and PE terminals 32 A 1 mm2 to

10 mm2, 63 A 16 mm2 to 50 mm2 and 100 A 16 mm2 to 95 mm2, red and orange terminals for DC

25 Output circuits26 Busbar isolator27 Dummy block and 18 mm cover with

DIN top for the additional socket28 Socket end piece on left and right29 Incoming terminal component, centre

power supply 200 A, maximum 95 mm2

30 Universal adapter with a current rating of 32 A, 63 A or 100 A

31 Combi module with a current rating of 32 A


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Pluggable devices on the SMISSLINE SystemMiniature circuit breaker S4001-, 2-, 3- and 4-pole devices with a current ratingBetween 0.5 A and 63 ACharacteristics B, C, D, K, UC-Z, UC-CSnap on auxiliary and signal contacts on theleft and rightRated switching capacity Icn: 6 kA (E) and 10 kA (M) Residual current device F402, F4042-pole residual-current circuit breaker 25 A to 40 A, 10, 30, 100 mA4-pole residual-current circuit breaker 25 A to 63 A, 30, 100, 300 mAShort time delay type FIK (does not react to discharge currents)Selective residual-current circuit breaker type S (selective to FI or FIK)

Combined RCBO FS401, FS403Rated breaking capacity kA (E) and 10 kA (M)Snap-on auxiliary and signal contacts on the leftShort time delayed versions FIK (does not react to discharge currents)

Surge arrester 404 OVR4-pole protection device, type 2Potential-free signal contact integrated in the deviceRated discharge surge current Isn 15 kA

Motor protection circuit breaker MS 325Power motor protection circuit breaker MS325 Un 690 V, In 0.1 to 25 A, breakingcapacity 100/50 kA, with phase failure protection, temperature.

Auxiliary and signal contactsThe plug-in socket system gives you the option of signaling via auxiliary busbars.The auxiliary busbars LA and LB can be contacted directly via contactingparts. The contacting parts can be easily changed from LA to LB by repluggingthem, or they can be removed completely. A collective alarm is possible using theinnovative collective alarm signal contact. To do this, contact is made parallel withthe auxiliary busbars.

Advantages of vertical construction compared to conventional layoutsLarger assemblies with SMISSLINE can be are arranged vertically. The power for the plug-in socket system is supplied via an incoming terminal block. Fewer cables are required for the cross connections in the control cabinet. The input wiring is integrated in the plug-in socket system. The N and PE terminals are directly assigned to the devices. The outgoing cables are connected directly to the devices. This results in an overall clear arrangement. Expansion is easy thanks to the plug-in technology.

Customer Benefits with SMISSLINE in Hospitals and ClinicsReliability and AvailabilityFast and easy handling with pluggable devicesPlug-in technology provides 24-hour service, 365 days a yearFreedom in concept and designMix of devices, various power supply optionsFlexible architecture without risk of damage to life and propertyUpgradeabilityEasy integration of new devices Upgrade without changing the existing installation

3.3.2 continued

48


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.3

DuctsIn group 2 medical locations the ducts installed inside the room must be purposed exclusively for the power supply of the electrical devices and their accessories present in the same room; in practice, ducts that supply power to equipment located in other rooms cannot pass through these group 2 medical locations.The circuits branching from an Medical IT system must necessarily be separated from the electrical circuits powered by other systems, and must, therefore, be installed in separate piping or ducts and boxes. The use of shared ducts and boxes is also allowed provided that the separation is implemented with an insulating separator (fig. 3.13).

Insulatingseparator

IT-Msystem circuit

Insulatingseparator

IT-Msystem circuit

Ordinarycircuit

Ordinarycircuit

The circuits of the Medical IT system can also be implemented using unipolar cables (cords) of the type N07V-K (with the warning not to use navy, blue or light blue conductors, since an Medical IT system never has Neutral).If it is impossible to implement a physical separation of two electrical systems, and the Medical IT circuit runs through a duct “shared” with the conductors of another system, double insulation cables with a non-metallic sheath must be used. In addition, if the leakage current is due to a capacitive effect, it is recommended that the protection conductor be separated from the phase conductors and then inserted in its own protective tube.

In group 2 medical locations where electromedical devices are used in order to monitor and support vital parameters, such as those of intensive care, resuscitation and similar, the devices should be powered using conductors that are shielded or inserted in metallic piping as a precaution against electrical fields. Both the shieldings of the cables as well as the metal piping must be equipotentialised on the nearest node or sub-node.For radiology and CAT rooms and rooms with equipment that emits ionising radiation, the power supply conductors should not interrupt the radiation shieldings present.The protection of the ducts against overcurrents must be implemented using omnipolar automatic miniature circuit breakers. Also in Medical IT systems, the circuits branched to the secondary must be protected with fuses or thermomagnetic automatic miniature circuit breakers, but not with RCDs because the RCD would not be effective in this particular “medical insulation” system.

Figure 3.13: Separation of Medical IT circuits from others by means of insulating separators


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

Power supply ducts for radiological or similar equipmentRadiological devices and those with a power consumption in excess of 5 kVA absorb high value currents from the power supply line. For this reason the sizing of the power supply conductors must be assessed carefully in order to contain voltage drops.Radiological devices of the fixed type and devices with power consumption greater than 5 kVA, powered directly by the “ordinary” network and in general without the interposition of a socket/plug group, can be protected with RCDs with a differential current of 0.5 A.If they may enter the patient environment it is mandatory to adopt differential 30 mA thermomagnetic miniature circuit breakers of type “A” (for single phase circuits) or “B” (especially for three-phase circuits).

3.3.5

Selectivity of the protection devicesParticular care must be taken in implementing effective selectivity of the overcurrent protection devices in order to guarantee maximum continuity of service.As far as possible, horizontal and vertical selectivity must be implemented. With horizontal selectivity, and therefore by subdividing the system into different circuits, downtime in the case of a malfunction is reduced. Subdivision into several circuits also makes it possible to prevent the simultaneous use of numerous devices connected to the same circuit from causing the tripping of the RCD (for example due to the capacitive earth leakages of the devices).A particular aspect of horizontal selectivity concerns group 2 rooms: the standards require that for every patient treatment position (such as a socket control panel, a wall-mounted power supply unit or the pensile stand) the plug sockets powered by the Medical IT System must be alternatively (fig. 3.14):– connected to two distinct power supply circuits (each equipped with the respective

protection device);– protected against overcurrents individually or in groups (at least two). With this provision, if a plug socket downstream fails, with tripping of the related protection device, only one socket or one group of sockets will be out of service, while the others remain in operation.Together with horizontal selectivity it is also necessary to guarantee vertical selectivity so that, in the event of overcurrent, only the device for protection of the circuit affected by the malfunction will trip, and not device the upstream (fig. 3.15).

Medical ITSystem

Medical ITSystem

Medical ITSystem

Only this Miniature circuit breaker must be tripped

3.3.4

Figure 3.14: Protection of sockets powered by the Medical IT Systema) subdivision into two separate

circuits protected individuallyb) protection in groupsc) single protection

Figure 3.15: Vertical selectivity in the presence of Miniature

circuit breakers in series.


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.5 continued

Selectivity in Medical IT circuits can be implemented with thermomagnetic switches or fuses of adequate size.When using fuses, their purpose is to protect each socket in the group and, upstream in the room switchboard, to protect the power supply duct for each group of sockets. Total selectivity is implemented by choosing fuses of the appropriate size and the main switch with a very high magnetic trip current.The advantages are obvious: if one considers that a short circuit in an operating room normally occurs because the plugs have been pulled out by tugging the cable instead of grasping the actual plug, or due to fluids entering into contact with active parts, a short-circuit on a socket causes tripping of the respective fuses, and therefore it is possible to use another socket (there are always more sockets than necessary) without any serious disservice.With the use of automatic miniature circuit breakers, selectivity can be obtained by choosing the protection devices so that for all the short circuit values, up to the maximum leakage current provided for on the duct protected by the downstream circuit-breaker, the tripping zones of the miniature circuit breakers in series do not overlap (fig. 3.16). In general, however, selectivity between circuit breakers is obtained also by regulating their tripping time delays.

time

miniature circuit breaker 1

miniature circuit 2



miniature circuit breaker 1 maximum assumed short circuit current

miniature circuit 2

current

Selectivity must also be implemented for the RCDs assigned to protect equipment powered directly by the network.For example, in the hospital accommodation rooms (group 1 rooms) there are three circuits (lighting, plug sockets, headboard sockets) each protected with a 30 mA RCD; to protect the power supply circuits for a group of rooms, a 300 mA RCD is installed, while upstream in the cabinet there is a 500 mA RCD. Lastly, total selectivity is obtained by regulating the tripping time delays of the RCDs.

3.3.6

Installation criteriaThe switchboard containing the insulating transformer can be installed either wall-mounted or floor-standing outside group 2 rooms, or inside provided that it is outside the patient environment, in order to avoid contact between the patient - including via medical personnel – and the cabinet, which contains not just the circuits downstream of the transformer, but also its power supply conductors.If the requirements demand power higher than that allowed (10 kVA) for the insulating transformer, then multiple insulating transformers must be installed in order to contain the leakage currents. In this way it is possible to benefit from the redundancy of the circuits in order to maximize continuity of service, also in the case of maintenance.The insulation monitoring and measuring device can be placed in the electrical switchboard of the Medical IT system, but a panel with repetition of acoustic/optical signals and a test pushbutton must be located in the most used premises, where the continuous presence of healthcare operators is assumed.Both the plug sockets and the miniature circuit breakers must be installed at more than 20 cm (from centre to centre) from any connection for gas for medical use.The plug sockets powered by an Medical IT system must not be interchangeable with the plug sockets of the same premises that are powered directly by the network.

Figure 3.16: Total selectivity between two miniature circuit breakers in series.


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.7

EarthingIn group 1 and 2 premises only the following appliances may be connected directly to the protection conductor (all the others must be connected to the equipotential node):- fixed appliances, such as ceiling lighting appliances in class 0 and I, as long as they are

installed more than 2.5m above the walking surface or completely outside the patient environment;

- limiters against overvoltages of any origin (it is advisable to install them on the incoming lines that supply power to the medical locations).

3.3.8

Safety servicesIn medical locations it is possible to use devices for which total availability of the power supply is required in order to avoid hazards for the patient in the case of malfunctions in the system or the devices, or in the event of a black-out.To obtain operational continuity following a malfunction, it is recommended to use an insula-ting transformer even in group 1 medical locations, in outpatient departments and in labora-tories, since it guarantees the use of electrical devices even if a “first earth fault” occurs in one of these. In analysis laboratories in particular, continuity is an essential factor because in the case of an interruption in the energy supply a long time is required for reprogramming and recommissioning them.To deal instead with an interruption of the power supply (black-out) an emergency system must be installed dedicated to the safety power supply for the loads defined as privileged because necessary for the safety of the patient.The characteristics of the safety power supply must be established by the designer, taking account of the real requirements of the healthcare structure to be served and the standards in force.In all group 2 (and in some group 1) medical locations, the safety power supply must be au-tomatic with a short interruption ( 0.5 s) and must guarantee the power supply of the lighting devices for operating tables, the electromedical devices that require a safety power supply and the monitoring and alarm systems for at least three hours.For other services and electromedical devices the safety power supply can have a medium interruption time, in other words with an activation time no longer than 15 s (safety lighting for exit routes, electromedical devices etc.), or a long interruption time, greater than 15 s (sterili-zation devices, refrigerators etc).The safety source may consist of batteries, uninterruptable power supplies (UPS) or electricity-generating units.In each operating room or group of rooms continuity of operation should be implemented with at least two UPS. In this way, each UPS works at 50% of its power, and is not therefore subject to overloads and can stand in for the other in the event of malfunctions.The use of multiple redundant UPS also benefits maintenance, which can be carried out on one group at a time, thus allowing the operating room to remain active.A further advantage offered by the UPS is the quality of the energy supplied, with a resulting absence of interference on the circuits downstream.The UPS are able supply power to the load without any interruption, but they normally have limited autonomy (10 ÷ 30 min) and therefore an electricity-generating unit intervenes after-wards (fig. 3.17).

Network Electricity-generating unit

Ordinaryloads

Privilegedloads

Lightingsystem

Medical ITloads

To the operating theatre

Figure 3.17: Safety power supply implemented with a UPS and an

electricity-generating unit.

Necessity for continuity <of operation


3

IMP

LEM

EN

TAT

ION

OF S

YS

TE

MS

IN M

ED

ICA

L LOC

AT

ION

S

3.3.9

Safety lightingSafety lighting is required in the following environments:- group 1 and group 2 medical locations.- exit routes and safety exits, including the associated safety signs;- rooms containing cabinets, electrical switchboards, production system sources;- rooms with essential services, such as elevator machinery, kitchens, air conditioning

stations, data processing centres;Safety lighting must enter into operation within the times specified by the standard (table 3.7).Safety lighting must be guaranteed via centralized systems (batteries or electricity-generating units) or by means of autonomous devices, individually equipped with a battery with an autonomy of at least 2 hours.The table specifies the tripping time delays for the safety power supply required by the standard in relation to the type of medical premises.

Type of premises Interruption

0,5 sInterruption

15 sMassage room (1)

Hospital accommodation rooms Delivery room (2)

ECG, EEG, EHG, EMG room Endoscopy room (2)

Outpatient departments (1)

Urology room Radiology diagnosis and radiotherapy rooms Hydrotherapy room Physiotherapy room Anaesthesia room (2)

Room for surgery (2)

Operation preparation room (2)

Surgical plaster room (2)

Post-operative waking room (2)

Room for applications of cardiac catheters (2)

Intensive care room (2)

Angiographic and haemodynamic analysis room (2)

Haemodialysis room Magnetic resonance room (MRI) Nuclear medicine room Premature infant room (2)

(1) Only for group 1 medical locations.(2) Lighting devices and electromedical devices with a life support function that require a

power supply within 0.5 s or less.

Table 3.7: Tripping time delays of the safety power supply in relation to the type of medical premises


4Other information on systems for medical locations

4.1

Veterinary premisesArea of application of the standards to veterinary premisesThe IEC 60364-7-710 specifi es that as far as it is practically applicable, the standard can also be used for veterinary clinics and surgeries”.Veterinary environments can have varying degrees of risk depending on the function that the veterinary medical manager wishes to assign to his studio or to the structure in which he carries on his activity. It is therefore the veterinary medical director who must defi ne the activity carried out in the various premises by means of a written declaration; the designer defi nes the systems to be implemented on the basis of the director's choices.

4.1.1

Electrical riskRegarding electrocution phenomena (direct and indirect contacts) animals present a higher or lower risk according to the species to you to which they belong, their size and the treatments or operations to which they are subjected, and in certain conditions (included heart operations on animals for research) they may also be subject to the risk microshock.The risk of microshock is normally particularly signifi cant in veterinary clinics, hospitals and research centres. In veterinary studios and laboratories, on the other hand:- intracardiac operations or operations that may involve the cardiac muscle are not

performed;- electromedical devices with applied parts are used with great moderation, while “electrical

devices” are used frequently, as well as their accessories such as shearing devices, portable electric drills, as are “electromedical devices” such as fi xed or trolley-supported scialytic lamps that enter the patient environment.

Figure 4.1: Example of a veterinary clinic


4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

4.1.1 continued

We can therefore conclude that veterinary studios and laboratories can always be considered as group 1 even if surgical operations can be carried out in them, while group 2 locations can be present in veterinary clinics, university hospitals with veterinary specialisation and in veterinary or clinico-pharmacological research centres.

Is it a premises where the veterinary examines the animal without using electrical devices, even if not strictly electromedical devices with applied parts (for example, electric razors) or which may enter the patient environment (for example, scialytic lamp)?

YESGroup 0 veterinaryroom (including animal accommodation rooms)

NO

Is the animal subjected to therapy and/or treatmentincluding invasive surgical operations using electrical or electromedical devices with applied parts or that enter the patient environment, but the risk of microshock is low?

YES Group 1 veterinarylocations

NO

Is the animal subjected to cardiac operations or treatment that could result in high risks ofmicroshock?

YESGroup 2 veterinarylocations also with a hazard of microshock

4.1.2

Criteria for sizing and protecting the electrical systemThe protective methods adopted for the locations, as specified by the IEC 60364-7-710, can also be applied to veterinary rooms, classified as previously mentioned.

4.1.3

The Medical IT system in veterinary roomsThe Medical IT system can be adopted for different requirements depending on the group to which the veterinary room belongs. If the room is declared as group 2 (microshock hazard) the system is mandatory. If the room belongs to group 1 the adoption of the Medical IT system may be advisable in order to guarantee the possibility of using certain electrical devices even if a “first earth fault” occurs in one of these.The adoption of a device that monitors the insulation of the part of system under the insulating transformer is mandatory for group 2 rooms and recommended for group 1 rooms.

4.1.4

Inspections in veterinary premisesAs for premises for human medical use, in the case of veterinary premises it is also mandatory to perform the initial and periodic inspections according to the provisions of the standards.

Figure 4.2 shows a flow diagram for choosing the group of the veterinary premises.


4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

4.2

Initial and periodic inspectionsThe electrical systems in medical locations must be inspected, both before commissioning and also after any modifications or repairs (initial inspections); thereafter, they must be checked at intervals (periodic inspections) pre-established by a technical expert, who may or may not be an employee of the healthcare structure, and the results of each inspection must be recorded.

4.2.1

Initial inspectionsThe electrical systems of group 0 rooms (ordinary systems) are only subject to the inspections required by IEC 60364. For the systems of the group 1 and group 2 rooms, in addition to the checks required for ordinary systems, the following checks must be performed:

Tests and checks to be carried out Group 1 premises

Group 2 premises

1 Functional tests on the insulation monitoring device and the optical and acoustic alarm system of the Medical IT system

–

2 Measurement of the leakage currents of the secondary no-load winding and on the casing of the transformers for medical use; the test is not necessary if it has already been carried out by the manufacturer of the transformer

–

3 Measurement of the resistance of the supplementary equipotential connections

–

4 Check of the continuity of the protection and equipotential conductors

–

5 Visual inspection to ensure that the other regulatory prescriptions specified by Section 710 of Standard 60364-7 have been respected

The checks are carried out on the basis of the design documentation which must include at least:- floor plans indicating the group to which each medical premises belongs;- floor plans indicating the position of the equipotential nodes with the related connections;- the wiring diagrams.

Functional testing of the Medical IT systemThe functional test of the insulation monitoring device is carried out through a series of assessments followed by a number of tests.

- the device must conform to the IEC 61557-8, concerning devices for testing, measurement and monitoring protective measures;

- the internal impedance of the device must not be lower than 100 kΩ;

- the supply voltage of the alarm circuit must not be higher than 25 V DC.

Initial assessments

Tests

a) measurement of the current circulating in the alarm circuit that, even in the event of a malfunction, must not be higher than 1 mA DC;

b) check that the alarm signal occurs when the insulation resistance drops below 50 kΩ.

Instrumentation <To carry out the tests and

measurements appropriate instrumentation is

required, including:- a Voltmeter;

- a milliammeter grip;- a milliohm meter with a

no-load voltage between 4 and 24 V in DC or AC and

test current of 10 A;- a device for testing the

circuit breakers


4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

Figure 4.4: Insulation controller trip test

Figure 4.3: Measurement of the current in the alarm circuit.

4.2.1 continued

a) Measurement of the current in the alarm circuit

Purpose of the test: It must guaranteed that, even in the case of a malfunction, the current in the circuit does not exceed the value of 1 mA DC.

Instrument: milliammeter.

Procedure: measurement of the current in the alarm circuit can be carried out in conditions of dead short earth fault by inserting the milliammeter in series with the conductor that connects the device to the equipotential node and connecting one of the conductors of the isolated circuit directly to earth (fig. 4.3).

insulating transformer

network 230 V/50 Hz

dead short connection

I 1 mA

insulation monitoring device

to the equipotential bonding bus bar

b) Trip test

Purpose of the test: to check that the insulation monitoring device is functioning correctly, in other words, that the alarm signal is activated when the insulation resistance value drops below 50 k .

Instrument: rheostat.

56 after disconnecting the loads, each conductor of the circuit powered by the secondary of the insulating transformer is connected - one at a time - with the equipotential node using the rheostat (fig. 4.4). Fault simulation is implemented by reducing the resistance of the rheostat to a value R < 50 k . This must cause the optical and acoustic alarm system to trip. Then, by increasing R up to values higher than 50 k , you can check that the alarm can be deactivated automatically.

230 V/50 Hz


network

insulation monitoring device



4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

Figure 4.5: Measurement of the leakage currents of the insulating

transformer

4.2.1 continued

Functional test of signalling systems

Purpose of the test: to check that the optical and acoustic alarm systems are functioning.

56 the test is performed by assessing, by means of a visual inspection, that the following prescriptions have been respected:- presence of the signalling indicator light, lit up green, indicating normal operation;- presence of the signalling indicator light, lit up yellow, which comes on when the alarm

device intervenes (insulation resistance < 50 k );- impossibility of switching off the yellow indicator light; it must switch off only after the

signalled fault has been eliminated;- presence of an acoustic signal that starts to function when the alarm device is tripped

(insulation resistance < 50 k ); the signal must be audible in the rooms of the department where medical personnel are expected to be present.

Measurement of the leakage currents of the insulating transformer

Purpose of the test: To check that the earth leakage current of the secondary winding and the casing of the insulation transformer is not higher than 0.5 mA.

Instrument: milliammeter.

Procedure:a) earth leakage of the secondary winding is measured with the transformer powered with

no load at the rated voltage, with the insulation monitoring device deactivated and by connecting the milliammeter between the equipotential node and each pole of the transformer one at a time (fig. 4.5).

b) the earth leakage on the casing is measured on the accessible metal parts that are not connected to earth (for example, rivets, screws etc.), and on the insulating parts by applying a metal sheet on these.

230 V/50 Hz

I 0.5 mA


network

insulation monitoring device (disconnected)



4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

Measurement of the supplementary equipotential connections (group 2 medical locations)In group 2 medical locations the resistance of each conductor for connection to the equipotential bonding bus bar must be measured.

Purpose of the test: to check that each connection between the equipotential node and the earth of the plug sockets, the earth terminal of fixed user devices and any extraneous conductive part has a resistance no higher than 0.2 .

Instrument: four terminal switchgear, working according to the volt-ammetric principle, with a no-load voltage between 4 and 24 V in a.c. or d.c. and capable of providing a current of at least 10 A.

Procedure: the terminals of the instrument are connected on one side to the equipotential bonding bus bar and on the other to the conductive part or extraneous conductive part, as indicated in figure 4.6. The test current is circulated by means of the ammetric circuit (terminals A1 and A2) while voltage is measured by means of the volumetric circuit (terminals V1 and V2). The pins must be located at two different points, both on the equipotential bonding bus bar and on the conductive part. In this way it is possible to measure not just the resistance Rc of the equipotential conductor, but also the contact resistances of the connections of the conductor itself (R1 and R2). In the presence of a subnode, the measurement must be performed between the equipotential bonding bus bar and the conductive part or extraneous conductive part; in other words, it must simultaneously involve both conductors - the one between the equipotential node and the sub-node and the one that connects the sub-node to the conductive part or extraneous conductive part (fig. 4.7).

V1

V2

A1

A2

RcR1 R2

V

A B

R1R2

Rc

A

AG

Measuring instrument

Sub-node

Equipotential conductor

Extraneous conductive part

Main node

4.2.1 continued

Figure 4.6: Measurement of the resistance of supplementary equipotential conductors.

Figure 4.7: Measurement of the equipotential connection of an extraneous conductive part through a sub-node.


4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

4.2.1 continued

Testing supplementary equipotential connections (group 1 medical locations)The test is performed by making sure that the connections of the protection and equipotential conductors and of the equipotential bonding bus bar are made correctly and that they are intact.

Purpose of the test: to check the electrical continuity of the conductors, in other words that there are no false contacts (without measuring their resistance).

Instrument: ohmmeter with a no-load voltage between 4 and 24 V in AC or DC and that supplies a current of at least 0.2 A.

Procedure: the terminals of the instrument are connected on one side to the equipotential bonding bus bar and on the other to the conductive part or extraneous conductive part, then a check is made to ensure that the current supplied from the instrument does not drop below 0.2 A.

Measurement for the identification of extraneous conductive parts

Purpose of the test: to assess whether a metal part is an extraneous conductive part by measuring resistance to earth. It is considered to be an extraneous conductive part if the resistance value measured is less than 0.5 M in group 2 medical locations and less than 200 in the group 1 medical locations.

Instrument: ohmmeter or appropriate tool equipped with a plug socket to be inserted in a socket of the system and with a sensor to be placed in contact with the possible extraneous conductive part.

Procedure: the measurement is taken by connecting one of the pins of the instrument to the equipotential bonding bus bar and the other on the metallic structure in question (fig. 4.8).

operatingroomequipotential

bonding bus bar

if R < 0.5 M

the structure is a extraneous conductive part

Visual inspectionThe visual inspection must address the following aspects in particular:- coordination of protection devices in TN and TT systems;- calibration of the protection devices.- characteristics of SELV and PELV systems;- fire safety devices;- circuit configurations for supplying power to plug sockets in group 2 medical locations;- identification of the plug sockets supplied by safety sources;- performance of the sources and devices for safety power supply and lighting.

Figure 4.8: Measurement of the earth resistance of

extraneous conductive parts.


4

OT

HE

R IN

FOR

MA

TIO

N O

N S

YS

TE

MS

FOR

ME

DIC

AL LO

CA

TIO

NS

4.2.2

Periodic inspectionsIn addition to detailed and precise prior maintenance, the medical locations also need periodic checks at specific time intervals. The purpose of the periodic checks is to ensure that the conditions of acceptability and standards compliance that were found during the initial checks are maintained, as well as to make sure of the correct operation of the safety devices and systems.Table 4.1 summarises the checks to be carried out on the electrical systems of medical locations, and the corresponding frequency required by IEC 60364-7-710. It is important to note that these checks are in addition to those required by IEC 60364 for ordinary systems.

Check Frequency

1 Functional test of the insulation monitoring devices (on Medical IT systems)

6 months

2 Check, by means of a visual inspection, of the calibration of adjustable protection devices

1 year

3 Measurements of the resistance of supplementary equipotential connections

3 years

4 Test that the RCDs intervene at the value of Idn 1 year

5 Functional test of the power supply to safety services with combustion engines: • no-load test • test with load (for at least 30 minutes)

1 month 4 months

6 Functional test of the power supply of battery-powered safety services, in accordance with the manufacturer’s instructions

6 months

4.2.3

Recording of the resultsThe dates and the results of both initial and periodic tests must be recorded on paper or electronic media and conserved over time, as required by article 710.6 of the IEC 60364-7-710.

Table 4.1: Periodic checks that must be carried out on the electrical systems of group 1 and group 2 medical locations.


Appendix

5.1

Logical path for the design of electrical systems in premises for medical use

Declaration of the healthcare manager on the type of healthcare operations that will be carried out in the medical locations

Definition of the type of medical location

Analysis of the risks deriving from electromagnetic fields, atmospheric discharges, overvoltage on the power supply, fire

Identification of the air conditioning ducts of the premises, and of the piping for medical gases or anything else

Identification of the patient environment

Determination by the healthcare manager of the electromedical devices that will be used in the room and the corresponding power absorption values

Subdivision of the electromedical devices between ordinary devices and devices that must be powered by an Medical IT system

Definition of the size of the insulating transformer according to the power of the equipment envisaged in the room

Identification of the conductive parts and extraneous conductive parts that must be connected to the equipotential node

Identification of the duct paths and the positions where the switchboards and the equipotential node are to be located as well as the spaces

required for maintenance

Identification of specific requirements or restrictions and of the possible need for screens against external electromagnetic fields

Sizing of the conductors and the protections

Choice of operating and protection equipment


5

AP

PE

ND

IX

5.2

Options for design The design of a hospital electrical system requires a careful appraisal of numerous factors that together guarantee a correct synthesis between two intrinsically antithetic aspects: protection and operational continuity.The hospital electrical system for group 2 medical locations has a high degree of complexity and must take account of coordination with the distribution upstream. It is the precise task of the designer to weigh up the possible design choices compatibly with the applicable standards and at the same time with the technical requirements.

As a support, a number of alternative types of installations that the designer may have to evaluate are outlined below, with the intention of illustrating the advantages and disadvantages of the various solutions and, where possible, to offer a qualitative suggestion.

Concentration of loads under a privileged line or separation of the privileged line from the UPS line.

It is advised to divide up the circuits as specified by IEC 60364-7-710 so that there will in any case be a dual power supply on the circuits of the operating room, even when the power absorbed by the non Medical IT loads can be considered as negligible in relation to the installed power.

Concentration Division• Less complexity of the system • Lower costs • No use of the RCD protecting the

dedicated lines for the lighting system and machinery with power consumption >5 kVA, such as, for example, radiological devices

• No selectivity on the secondary UPS

• Redundancy of the circuits • Continuity of service: if the RX does not

function, the lines of the emergency section operate normally in any case

• Reduction of the power consumption of the medical insulating transformer

• Reduction of the size of the protection devices inside the Medical IT board


Ordinaryloads

Privilegedloads

Lightingsystem

MedicalIT loads

operating theatre


Ordinaryloads

Privilegedloads

Lightingsystem

MedicalIT loads

operating theatre


5

AP

PE

ND

IX

The choice of the most suitable protection device depends on the application context and must be prescribed by the designer. In intensive therapy premises, in which the patients have an extended stay in hospital, it is advisable to service the loads with multiple transformers, both to increase continuity of service and in order to be able to carry out maintenance operations, which must not cause disturbance to the patients.In the surgical outpatient departments, on the other hand, it may be appropriate to distribute the power supply from a single transformer, because the amounts of power absorbed are generally very limited and it is possible to manage a power reserve also with a 3 or 5 kVA insulating transformer. In these rooms, however, there is very limited space in which to position the switchboard, and therefore it may be preferable to prefer a switchboard with small dimensions.

Concentration or distribution of power in group 2 medical locations

Concentration Distribution• Reduction in the number of switchboards• Reduction of dimensions• Power available for future expansions of

the system• Lower costs

• Redundancy• Greater continuity of service• Ease of maintenance• Quicker fault finding• Reduction of the dimensions of the

individual switchboard• Easier to install wall-mounted

switchboard

Socketunit

Socketunit

Socketunit

Socketunit

Socketunit

Socketunit

Socketunit

Socketunit

The choice of the most suitable protection device depends on the application context and must be evaluated by the designer taking account of the above considerations.

Protection of Medical IT circuits by means of fuses or miniature circuit breakers

Fuses Miniature circuit breakers• High breaking capacity• Speed of activation• Selectivity with the socket units on

shelves, headboard and control panels of the room

• Better horizontal and vertical selectivity of the circuits

• Replacement of the damaged part only• The device is not affected by the

malfunction since the damaged cartridge has been replaced

• Possibility to section the line with a load by means of a device with an AC-22B usage category

• Instantaneous rearming• Speed of maintenance: no need to

replace the active parts• No special skills required for maintenance• Calibration of the protection device

cannot be altered by the user through replacement of components

• Possibility of installing numerous accessories including signal contacts

5.2 continued


5

AP

PE

ND

IX

It is strongly recommended to protect the power line of the insulation monitoring device by means of an appropriately coordinated fuse block base.To avoid deactivation of the insulation monitoring device while the IT-M circuit is functioning, it is advisable to install the fuse block in an inaccessible part of the switchboard, typically on the back of switchboard door. For the same reason, it is important that the fuse block base is not subject to sectioning and is lead-sealed in the closed position: in this way it is guaranteed that the power supply of the insulation monitoring device can only be cut off when the transformer secondary, and therefore the operating room, is not in operation.

Protection of the insulation monitoring deviceing device against short circuit and overload

Protect Do not protect• Possible overloads and short circuits are

avoided• Breakage of the insulation monitoring

device is avoided• Fire principles are avoided inside the

switchboard• Operational continuity to the Medical IT

circuits is guaranteed

• Cost of protection devices• Internal dimensions of the switchboard• Risk of making the protection device

ineffective if an inappropriate fuse is used• Risk of breakage of the insulation

monitoring device due to overload or contained short circuit

Auxiliarypower supply

Controlcircuit

Insulationmonitoring device

Auxiliarypower supply

Controlcircuit

Insulationmonitoring device

It is always advised to use an RCD on all non Medical IT circuits: RCDs in fact enable protection against fire risks and make it possible to contain a malfunction within the affected circuit, without causing more serious repercussions to the system upstream.

Protection of non Medical IT circuits by means of a Residual Current Device (RCD)

RCD use No RCD• By using an RCD with Idn = 0.03 A

additional protection against direct contacts is also guaranteed

• Protection against fire risks with Idn 0.5 A• Isolation of the malfunction inside the

circuit involved• Selective coordination between RCDs

• No untimely tripping• Conformance to protection against

indirect contacts is guaranteed, in TN systems, by thermomagnetic switches

• Essential configuration of the system• Reduction of periodic checks• Selectivity on indirect contacts to be

implemented by means of thermomagnetic switches

5.2 continued


5

AP

PE

ND

IX

5.3Leggi e decreti

Electromedical devices with applied parts

The following table lists the power consumption values of the main electromedical devices installed in operating rooms.As can be seen, the overall power required is close to 13 kW and this involves the use of at least two medical insulating transformers.

Power installed in a heart surgery operating roomDefibrillator 320 WInfusion pumps 50 WDisplay 100 WXenon light source 1500 WElectroscalpel monitor 1300 WLocal power source (monitoring) 2500 WBlood heat exchanger 2400 WExtracorporeal pumps 160 WAir heating for patient - Thermacare 1400 WN.3 scialytic lamps 450 WNegativoscope 200 WTotal installed power 10380 WN.B. Power consumptions to be considered with a simultaneous execution factor of 1, as specified by the standard

5.4

Laws and decreesIEC, CENELEC standards

EN 50110-1Operation of electrical installations

IEC 60947-2 Low-voltage switchgear and controlgear - Part 2: Circuit-breakers

IEC 61008-1Residual current operated circuit-breakers without integral overcurrent protection for household and similar uses (RCCBs) - Part 1: General rules

IEC 60079-10-1Explosive atmospheres - Part 10-1: Classification of areas - Explosive gas atmospheres

IEC 60598-1Luminaires - Part 1: General requirements and tests

IEC 60598-2-22Luminaires - Part 2-22: Particular requirements - Luminaires for emergency lighting

IEC 60598-2-25Luminaires - Part 2: Particular requirements - Section 25: Luminaires for use in clinical areas of hospitals and health care buildings

IEC 60601-1Medical electrical equipment - Part 1: General requirements for basic safety and essential performance

IEC 60601-2-21Medical electrical equipment - Part 2: Particular requirements for the safety of infant radiant warmers

IEC 60601-2-27Medical electrical equipment - Part 2: Particular requirements for the safety, including essential performance, of electrocardiographic monitoring equipment

IEC 60601-2-46Medical electrical equipment - Part 2-46: Particular requirements for the safety of operating tables


5

AP

PE

ND

IX

IEC 60601-2-41Medical electrical equipment - Part 2: Particular requirements for the safety of surgical luminaires and luminaires for diagnosis

IEC 364-4-444Electrical installations of buildings - Protection against electromagnetic interferences (EMI) in installations of buildings

IEC 60364Electrical installations of buildings - Part 1: Scope, object and fundamental principles

IEC 62305-1Protection against lightning. Part 1: General principles

IEC 62305-2Protection against lightning. Part 2: Risk management

IEC 62305-3Protection against lightning: Part 3: Physical damage to structures and life hazards

IEC 62305-4Protection against lightning: Part 4: Electrical and electronic systems within structures

IEC 61557-8Electrical safety in low voltage distribution systems up to 1 000 V a.c. and 1 500 V d.c. - Equipment for testing, measuring or monitoring of protective measures - Part 8: Insulation monitoring devices for IT systems

IEC 61558-1Safety of power transformers, power supplies, reactors and similar products - Part 1: General requirements and tests

IEC 61558-2-15Safety of power transformers, power supply units and similar - Part 2-15: Particular requirements for isolating transformers for the supply of medical locations

5.4.1

ISO, CEN standards

EN 737-3Systems for distribution of medical gases - Systems for compressed medical gases and vacuum

EN 838Applications of lighting technology. Emergency lighting

ISO 11197Power supply units for medical use

EN 12464-1Light and lighting systems - Lighting in the workplace - Part 1: Internal work places

5.4 continued

H+

Lin

e P

ractical guide for group

2 med

ical locations H+LinePractical guide for group 2 medical locations

2CS

C47

0010

B02

02 -

08/

2012

- 1

.000

Pz.

Contacts

ABB SACEA division of ABB S.p.A.Modular DevicesViale dell’Industria, 1820010 Vittuone (MI) - ItalyTel.: +39 02 9034 1Fax: +39 02 9034 7609

www.abb.com

Data and images are not binding. Depending on technical development and the products, we reserve the right to modify the content of this document without notice.

Copyright 2012 ABB. All right reserved.

H+Line Practical Guide for Group 2 Medical Locations

Documents

Transcript of H+Line Practical Guide for Group 2 Medical Locations